- Whole seeds of Bauhinia variegata L. (Fabaceae) as an efficient biocatalyst for benzyl alcohol preparations from benzaldehydes
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Whole seeds of Bauhinia variegata L. (Fabaceae) were utilized as a biological reducer to transform benzaldehyde into benzyl alcohol. The effects of some variables such as temperature, the load of substrate and co-solvent, were established to optimize the reductive process. Utilizing the optimal reaction conditions, a laboratory-scale reaction (final concentration of the substrate: 21.2 mM) was performed to obtain benzyl alcohol (conversion: 95%; isolated yield: 49%; productivity: 1.11 g L?1 or 0.046 g L?1h?1 of benzyl alcohol). In addition, using these optimal conditions, fourteen substituted benzaldehydes were reduced, with a conversion achieved to their corresponding benzyl alcohols ranging from 62% to >99% (isolated yields from 7% to 70%). Moreover, useful building blocks by the synthesis of the drugs and important commercial products were also obtained. The scope, limitations and advantages of this new biocatalytic synthetic method are also discussed.
- Aimar, Mario L.,Bordón, Daniela L.,Díaz Panero, Mariángeles,Decarlini, María F.,Demmel, Gabriel I.,Rossi, Laura I.,Vázquez, Ana M.
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- Highly dispersed ultrafine palladium nanoparticles encapsulated in a triazinyl functionalized porous organic polymer as a highly efficient catalyst for transfer hydrogenation of aldehydes
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Fabrication of highly dispersed ultrafine noble metal nanoparticle (NMNP) based catalysts with high stability and excellent catalytic performance is a challenging issue for heterogeneous catalysis. As an alternative complement to existing solutions, herein, we designed and synthesized a stable triazinyl-pentaerythritol porous organic polymer (TP-POP) through a facile polycondensation between cyanuric chloride and pentaerythritol. The obtained TP-POP material has a three-dimensional folded structure, rich triazinyl groups, abundant hydrophobic pores and high thermal stability. Ultrafine Pd NPs with a narrow size distribution (1.4-2.8 nm) are then successfully confined in the organic pores of the TP-POP, through a reversed double solvent approach (RDSA). It is worth noting that the current strategy can effectively confine Pd NPs in the inner space of the TP-POP, and successfully avoids the agglomeration of Pd NPs as compared with the common impregnation-reduction method. The as-prepared Pd@TP-POP catalyst shows excellent catalytic activity in the reduction of 4-nitrophenol and transfer hydrogenation of aromatic aldehydes under very mild conditions. The excellent performance of the Pd@TP-POP catalyst is attributed to the abundant mesopores of the TP-POP which can enhance the accessibility of the highly dispersed ultrafine Pd NP active sites that are confined in the organic pores. More importantly, the Pd@TP-POP catalyst is easily recycled and highly stable without loss of its catalytic activity even after ten reaction cycles. Therefore, this study provides a new platform for designing and fabricating stable POP materials to confine size-controlled NMNPs with superior catalytic performance for various potential catalysis applications.
- Yang, Jin,Yuan, Man,Xu, Dan,Zhao, Hong,Zhu, Yangyang,Fan, Menying,Zhang, Fengwei,Dong, Zhengping
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- Biotransformation of aromatic aldehydes by five species of marine microalgae
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The biotransformation of a series of aromatic aldehydes such as benzaldehyde, salicy aldehyde, methoxybenzaldehydes and mono- and dichlorobenzaldehydes by five cultures of photosynthetic microalgae are reported. The microalgae, Chlorella minutissima, Nannochloris atomus, Dunaliella parva, Porphyridium purpureum and Isochrysis galbana, reduced most of the aldehydes to the corresponding primary alcohols. Substituted aromatic aldehydes were reduced with varying selectivity depending on the nature and position of the substituent.
- Hook, Ingrid L.,Ryan, Shane,Sheridan, Helen
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- Reduction of aldehydes and ketones to corresponding alcohols using diammonium hydrogen phosphite and commercial zinc dust
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A mild and an efficient system has been developed for the reduction of aromatic aldehydes and ketones to their corresponding alcohols in good yield using inexpensive commercial zinc dust as catalyst and diammonium hydrogen phosphite as a hydrogen donor.
- Kumar, K. Anil,Gowda, D. Channe
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Read Online
- Synthesis and catalytic activity of N-heterocyclic silylene (NHSi) iron (II) hydride for hydrosilylation of aldehydes and ketones
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A novel silylene supported iron hydride [Si, C]FeH (PMe3)3 (1) was synthesized by C (sp3)-H bond activation with zero-valent iron complex Fe (PMe3)4. Complex 1 was fully characterized by spectroscopic methods and single crystal X-ray diffraction analysis. To the best of our knowledge, 1 is the first example of silylene-based hydrido chelate iron complex produced through activation of the C (sp3)?H bond. It was found that complex 1 exhibited excellent catalytic activity for hydrosilylation of aldehydes and ketones. The catalytic system showed good tolerance and catalytic activity for the substrates with different functional groups on the benzene ring. It is worth mentioning that, the experimental results showed that both ketones and aldehydes could be reduced in good to excellent yields under the same catalytic conditions. Based on the experiments and literature reports, a possible catalytic mechanism was proposed.
- Du, Xinyu,Qi, Xinghao,Li, Kai,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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- Synthesis, Docking, and Biological activities of novel Metacetamol embedded [1,2,3]-triazole derivatives
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ERα controls the breast tissue development and progression of breast cancer. In our search for novel compounds to target Estrogen Receptor Alpha Ligand-Binding Domain, we identified “N-(3-((1H-1,2,3-triazol-4-yl)methoxy)phenyl)acetamide” derivatives as lead compounds. The Docking studies indicated good docking score for Metacetamol derivatives when docked into the 1XP6. A series of metacetamol derivatives have been synthesized, characterized and evaluated for cytotoxicity, anti bacterial and anti oxidant activities. Among the tested twelve hybrid compounds, “7a, 7g, 7h and 7i” derivatives showed promising cytotoxicity with IC50 value of 50 value of 30 μM, whereas Compounds “7a, 7b, 7c, 7d, 7g, 7j, 7k and 7l” showed moderate anti bacterial activity with the MIC value of 300 μM.
- Battu, Satyanarayana,Joolakanti, Hima Bindhu,Kamepalli, Ramanjaneyulu,Miryala, Jeevanreddy
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- Pyridine: N-oxide promoted hydrosilylation of carbonyl compounds catalyzed by [PSiP]-pincer iron hydrides
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Five [PSiP]-pincer iron hydrides 1-5, [(2-Ph2PC6H4)2HSiFe(H)(PMe3)2 (1), (2-Ph2PC6H4)2MeSiFe(H)(PMe3)2 (2), (2-Ph2PC6H4)2PhSiFe(H)(PMe3)2 (3), (2-(iPr)2PC6H4)2HSiFe(H)(PMe3) (4), and (2-(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (5)], were used as catalysts to study the effects of pyridine N-oxide and the electronic properties of [PSiP]-ligands on the catalytic hydrosilylation of carbonyl compounds. It was proved for the first time that this catalytic process could be promoted with pyridine N-oxide as the initiator at 30 °C because the addition of pyridine N-oxide is beneficial for the formation of an unsaturated hydrido iron complex, which is the key intermediate in the catalytic mechanism. Complex 4 as the best catalyst shows excellent catalytic performance. Among the five complexes, complex 3 was new and the molecular structure of complex 3 was determined by single crystal X-ray diffraction. A proposed mechanism was discussed.
- Chang, Guoliang,Fenske, Dieter,Fuhr, Olaf,Li, Xiaoyan,Sun, Hongjian,Xie, Shangqing,Yang, Wenjing,Zhang, Peng
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p. 9349 - 9354
(2020/09/09)
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- Synthesis and Catalytic Activity of Iron Hydride Ligated with Bidentate N-Heterocyclic Silylenes for Hydroboration of Carbonyl Compounds
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We report the synthesis of a novel bidentate N-heterocyclic silylene (NHSi) ligand, N-(LSi:)-N-methyl-2-pyridinamine (1) (L = PhC(NtBu)2), and the first bischelate disilylene iron hydride, [(Si,N)(Si,C)Fe(H)(PMe3)] (2), and monosilylene iron hydride, [(Si,C)Fe(H)(PMe3)3] (2′), through Csp2-H activation of the NHSi ligand. Compounds 1 and 2 were fully characterized by spectroscopic methods and single-crystal X-ray diffraction analysis. Density functional theory calculations indicated the multiple-bond character of the Fe-Si bonds and the π back-donation from Fe(II) to the Si(II) center. Moreover, the strong donor character of ligand 1 enables 2 to act as an efficient catalyst for the hydroboration reaction of carbonyl compounds at room temperature. Chemoselective hydroboration is attained under these conditions. This might be the first example of hydroboration of ketones and aldehydes catalyzed by a silylene hydrido iron complex. A catalytic mechanism was suggested and partially experimentally verified.
- Qi, Xinghao,Zheng, Tingting,Zhou, Junhao,Dong, Yanhong,Zuo, Xia,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 268 - 277
(2019/01/21)
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- Facile reduction of carboxylic acids to primary alcohols under catalyst-free and solvent-free conditions
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We report the development of a facile protocol for the deoxygenative hydroboration of aliphatic and aryl carboxylic acids to afford corresponding primary alcohols under solvent-free and catalyst-free conditions. The reaction proceeds under ambient temperature exhibits good tolerance towards various functional groups and generates quantitative yields. The plausible mechanism involves the formation of Lewis acid-base adducts as well as the liberation of hydrogen gas.
- Harinath, Adimulam,Bhattacharjee, Jayeeta,Panda, Tarun K.
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supporting information
p. 1386 - 1389
(2019/02/05)
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- Efficient transfer hydrogenation of carbonyl compounds catalyzed by selenophenolato hydrido iron(II) complexes
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Selenophenolato hydrido iron(II) complexes 1–3 cis-[(H)(SeAr)Fe(PMe3)4] (Ar = C6H5 (1), p-MeOC6H4 (2) and o-MeC6H4 (3)) could catalyze transfer hydrogenation of aldehydes and ketones. Among the three complexes, catalyst 1 exhibited the highest catalytic activity. The catalytic reactions took place under very mild conditions, using isopropanol as solvent and hydrogen source, tBuONa as base under 60–80 °C. This catalytic system has good tolerance for many functional groups, such as halides, C[dbnd]C double bonds, nitro groups and cyano groups at the phenyl ring of the substrates.
- Wang, Yangyang,Du, Zhengyin,Zheng, Tingting,Sun, Hongjian,Li, Xiaoyan
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- Sulfonic acid anchored on silica, SiO2@SO3H: A superior solid acid catalyst for quick and solvent-free reductive-deoxygenation of ketones with NaBH3CN
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NaBH3CN as a modified hydroborate agent and due to a strong withdrawing CN group does not show any reducing ability to reduce functional groups in the absence of acidic media (pH ~ 3–4). In this study, the immobilized sulfonic acid on silica, SiO2@SO3H, was prepared and applied as a new solid acid catalyst for extremely enhancing the reducing ability of NaBH3CN. The influence of SiO2@SO3H was highlighted by performing the quick and green reduction of structurally diverse carbonyl compounds involving aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones, and acyloins to the corresponding alcohols or alkanes with NaBH3CN. By the NaBH3CN/SiO2@SO3H system, aldehydes were reduced to the corresponding alcohols and ketonic compounds to alkanes as reductive-deoxygenation products. All reduction reactions were carried out within 3 min at room temperature and under solvent-free conditions to afford the products in high to excellent yields (90–98%).
- Zeynizadeh, Behzad,Kouhkan, Mehri
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p. 1521 - 1528
(2018/11/23)
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- Methanol as hydrogen source: Transfer hydrogenation of aromatic aldehydes with a rhodacycle
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A cyclometalated rhodium complex has been shown to perform highly selective and efficient reduction of aldehydes, deriving the hydrogen from methanol. With methanol as both the solvent and hydrogen donor under mild conditions and an open atmosphere, a wide range of aromatic aldehydes were reduced to the corresponding alcohols, without affecting other functional groups.
- Aboo, Ahmed H.,Bennett, Elliot L.,Deeprose, Mark,Robertson, Craig M.,Iggo, Jonathan A.,Xiao, Jianliang
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supporting information
p. 11805 - 11808
(2018/11/10)
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- Transfer hydrogenation of aldehydes catalyzed by silyl hydrido iron complexes bearing a [PSiP] pincer ligand
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The synthesis and characterization of a series of silyl hydrido iron complexes bearing a pincer-type [PSiP] ligand (2-R2PC6H4)2SiH2 (R = Ph (1) and iPr (5)) or (2-Ph2PC6H4)2SiMeH (2) were reported. Preligand 1 reacted with Fe(PMe3)4 to afford complex ((2-Ph2PC6H4)SiH)Fe(H)(PMe3)2 (3) in toluene, which was structurally characterized by X-ray diffraction. ((2-iPr2PC6H4)SiH)Fe(H)(PMe3) (6) could be obtained from the reaction of preligand 5 with Fe(PMe3)4 in toluene. Furthermore, complex ((2-iPr2PC6H4)Si(OMe))Fe(H)(PMe3) (7) was isolated by the reaction of complex 6 with 2 equiv. MeOH in THF. The molecular structure of complex 7 was also determined by single-crystal X-ray analysis. Complexes 3, 4, 6 and 7 showed good to excellent catalytic activity for transfer hydrogenation of aldehydes under mild conditions, using 2-propanol as both solvent and hydrogen donor. α,β-Unsaturated aldehydes could be selectively reduced to corresponding α,β-unsaturated alcohols. The catalytic activity of penta-coordinate complex 6 or 7 is stronger than that of hexa-coordinate complex 3 or 4.
- Zhang, Peng,Li, Xiaoyan,Qi, Xinghao,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 14092 - 14099
(2018/04/25)
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- Hydrogenation and Reductive Amination of Aldehydes using Triphos Ruthenium Catalysts
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An air-stable and readily accessible ruthenium dihydride complex catalyses aldehyde hydrogenation under neutral conditions. A high activity has been shown in a number of examples, and solvent-free conditions are also applicable, which favours industrial-scale applications. The catalyst has also been demonstrated to be active at low catalyst loadings for the reductive amination of aldehydes under mildly acidic conditions. A number of examples of chemoselectivity challenges are also presented in which the catalyst does not reduce carbon?halogen groups, alkene or ketone functionality. The advantage of using the pre-formed complex, Triphos-Ru(CO)H2 (1), over in situ formed catalysts from Triphos and Ru(acac)3 (acac=acetylacetonate) is also shown in terms of both chemoselectivity and activity, in particular this can be seen if low reaction temperatures are used.
- Christie, Francesca,Zanotti-Gerosa, Antonio,Grainger, Damian
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p. 1012 - 1018
(2018/01/27)
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- Nonenzymatic Dynamic Kinetic Resolution of in situ Generated Hemithioacetals: Access to 1,3-Disubstituted Phthalans
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The first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa-Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3-disubstituted-1,3-dihyroisobenzofuran products were obtained in good yields with moderate diastereoselectivities and high enantioselectivities. (Figure presented.).
- Nath, Utpal,Chowdhury, Deepan,Pan, Subhas Chandra
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supporting information
p. 1628 - 1633
(2018/03/21)
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- Syntheses of hydrido selenophenolato iron(II) complexes and their catalytic application in hydrosilylation of aldehydes and ketones
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Three novel selenophenolato hydrido iron(II) complexes [cis-(H)(SeAr)Fe(PMe3)4] (4–6) (Ar=C6H5 (4), p-MeOC6H4 (5) and o-MeC6H4 (6)) were prepared through the reaction of Fe(PMe3)4 with selenophenols ArSeH (1–3) via Se–H activation. The iron hydrido complexes 4, 5 and 6 could catalyze the hydrosilylation of aldehydes and ketones. Among them complex 5 is the best catalyst for this process. Furthermore, α,β-unsaturated alcohols could be obtained from the selective reduction reactions of the corresponding α,β-unsaturated carbonyls catalyzed by hydrido iron(II) complex 5. This catalytic system has good tolerance for some common groups but it is easy to reduce the nitro group to an amino group. The experiments indicate that the chemoselectivity for this catalytic system is –CHO>–NO2>–C([dbnd]O)CH3. The crystal structure of 6 was determined by X-ray diffraction.
- Wang, Yangyang,Ren, Shishuai,Zhang, Wenbo,Xue, Benjing,Qi, Xinghao,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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- Synthesis and catalytic application of [PPP]-pincer iron, nickel and cobalt complexes for the hydrosilylation of aldehydes and ketones
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A new synthetic strategy for the novel diphosphine-phosphine oxide ligand (1) (Ph2P-(C6H4))2P(O)H was designed. A series of [PPP]-pincer Fe, Ni, and Co complexes were prepared. All of them were formed by chelate-assisted P-H activation. Two metal hydrides [(Ph2P-(C6H4))2P(O)]Fe(H)(PMe3)2 (2) and [(Ph2P-(C6H4))2P(O)]Ni(H)(PMe3) (3) were obtained at room temperature. The combination of ligand 1 with Co(PMe3)4Me or Co(PMe3)4 afforded the same Co(i) complex [(Ph2P-(C6H4))2P(O)]Co(PMe3)2 (4) via P-H bond activation. The catalytic performance of the Fe, Ni, and Co complexes for the hydrosilylation of aldehydes and ketones was explored. At a catalyst loading of 2 mol%, complex 2 displayed the best catalytic activity for the hydrosilylation by using (EtO)3SiH as the hydrogen source under mild conditions. Complexes 2, 3, and 4 were characterized by spectroscopic methods and X-ray diffraction analysis.
- Qi, Xinghao,Zhao, Hua,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 16583 - 16590
(2018/10/23)
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- Nickel boride mediated chemoselective deprotection of 1,1-diacetates to aldehydes and deprotection with concomitant reduction to alcohols at ambient temperature
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A variety of 1,1-diacetates have been chemoselectively and efficiently deprotected to the corresponding aldehydes as well as deprotected and concomitantly reduced to the corresponding alcohols in high yields at ambient temperature with nickel boride generated in situ using different molar ratios of sodium borohydride and nickel (II) chloride in methanol at room temperature. Deprotection and reduction of a variety of aromatic, aliphatic and heterocyclic acylals have been achieved efficiently. Mild reaction conditions, easy work-up, high yields and chemoselectivity demonstrate the efficiency of this new method.
- Bartwal, Gaurav,Saroha, Mohit,Khurana, Jitender.M.
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- Magnetic nanoparticle-supported DABCO tribromide: A versatile nanocatalyst for the synthesis of quinazolinones and benzimidazoles and protection/deprotection of hydroxyl groups
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1,4-Diazabicyclo[2.2.2]octane tribromide supported on magnetic Fe3O4 nanoparticles (MNPs-DABCO tribromide) as a novel heterogeneous tribromide type compound was found to be an efficient and reusable nanocatalyst for the one-pot synthesis of 2-arylquinazolin-4(3H)-ones and 2-aryl-1H-benzo[d]imidazoles through oxidative cyclization of aldehydes with 2-aminobenzamides and 1,2-phenylenediamine, respectively. Also, MNPs-DABCO tribromide catalyzed trimethylsilylation/tetrahydropyranylation and desilylation/depyranylation of a wide variety of alcohols and phenols through changing the solvent medium at room temperature.
- Rostami, Amin,Pourshiani, Omid,Navasi, Yahya,Darvishi, Neda,Saadati, Shaghayegh
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p. 9033 - 9040
(2017/08/29)
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- Catalytic hydrosilylation of carbonyl compounds by hydrido thiophenolato iron(II) complexes
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The hydrosilylation of aldehydes and ketones under mild conditions with hydrido thiophenolato iron(II) complexes [cis–Fe(H)(SAr)(PMe3)4] (1–4) as catalysts is reported using (EtO)3SiH as an efficient reducing agent in the yields up to 95%. Among them complex 1 is the best catalyst. Complex 1 could also be used as catalyst to reduce the α,β-unsaturated carbonyl compounds selectively to the α,β-unsaturated alcohols in high yields.
- Xue, Benjing,Sun, Hongjian,Niu, Qingfen,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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- Supported N-propylsulfamic acid onto Fe3O4 magnetic nanoparticles as a reusable and efficient nanocatalyst for the protection/deprotection of hydroxyl groups and protection of aldehydes
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N-propylsulfamic acid supported onto Fe3O4 magnetic nanoparticles (MNPs-PSA) as an efficient and magnetically reusable nanocatalyst has been reported for the tetrahydropyranylation/depyranylation of a wide variety of alcohols and phenols by changing the solvent medium. Also, the protection of aldehydes as acylals using Ac2O in the presence of catalytic amount MNPs-PSA in good to high yields at room temperature under solvent-free conditions is described. After completing the reaction, the catalyst was easily separated from the reaction mixture with the assistance of an external magnetic field and reused for several consecutive runs without significant loss of their catalytic efficiency.
- Rostami, Amin,Tahmasbi, Bahman,Abedi, Fatemeh
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p. 3689 - 3701
(2016/04/05)
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- Selective C-F and C-H Activation of Fluoroarenes by Fe(PMe3)4 and Catalytic Performance of Iron Hydride in Hydrosilylation of Carbonyl Compounds
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The reactions of perfluorinated toluene (CF3C6F5), pentafluoropyridine (C5NF5), and hexafluorobenzene (C6F6) with the iron(0) complex Fe(PMe3)4 were investigated. The Fe(I) complexes (4-CF3C6F4)Fe(PMe3)4 (1), (4-C5NF4)Fe(PMe3)4 (2), and (C6F5)Fe(PMe3)4 (3) were obtained by selective activation of the C-F bonds. However, under similar reaction conditions, the reaction of Fe(PMe3)4 with perfluoronaphthalene (C10F8) afforded a π-coordinated Fe(0) complex, (η4-1,2,3,4-C10F8)Fe(PMe3)3 (4), and the expected C-F bond activation reaction was not observed. The expected iron hydride (C6F5)FeH(PMe3)4 (6) could be obtained in a yield of 80% by the reaction of bromopentafluorobenzene with Fe(PMe3)4 and subsequent reduction with NaBH4. The molecular structures of complexes 2, 4, and 6 were determined by single-crystal X-ray diffraction. Complexes 1-4 and 6 could be used as catalysts for the hydrosilylation of carbonyl compounds. Among them, complex 6 is the best catalyst. The selective reduction of carbonyl groups of α,β-unsaturated aldehydes and ketones was also realized with 6 as catalyst.
- Zheng, Tingting,Li, Junye,Zhang, Shumiao,Xue, Benjing,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 3538 - 3545
(2016/11/06)
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- Technological method for preparing halogenated-3,4-dihydro-1H-2-naphthalenone
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The invention relates to a technological preparation method of halogenated-3,4-dihydro-1H-2-naphthalenone as shown in a formula (I). (As shown in the description). According to the method disclosed by the invention, through a cheap raw material namely 2,4-dihalogeno-benzene carbonitrile, and an intermediate namely 2,4-dihalogeno-benzene acetic acid is synthesized, and through a reusable trifluoroacetic anhydride/acid system catalyst, a target product namely the halogenated-3,4-dihydro-1H-2-naphthalenone is synthesized. According to the method disclosed by the invention, a large quantity of catalysts such as aluminumtrichloride, and costly catalysts such as Rh, are not needed, and the reaction route can be shortened, so that a large quantity of reagents and time can be saved, and the industrial economic benefits can be greatly increased.
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- Syntheses and catalytic application of hydrido iron(ii) complexes with [P,S]-chelating ligands in hydrosilylation of aldehydes and ketones
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Four hydrido iron(ii) complexes (1-4) with [P,S]-chelating ligands were synthesized by the reactions of (2-diphenylphosphanyl)thiophenols, C6H3(1-SH) (2-PPh2) (4-R1) (6-R2), abbreviated as (P^SH), with Fe(PMe3)4. (1: R1 = R2 = H; 2: R1 = H, R2 = SiMe3; 3: R1 = CH3, R2 = H; 4: R1 = SiMe3, R2 = H). Among them, complexes 2-4 are new and were completely characterized by spectroscopic methods. The molecular structures of complexes 2, 3, and 4 were confirmed by X-ray single crystal diffraction. The catalytic properties of hydrido iron(ii) complexes 1-4 were explored in the hydrosilylation of aldehydes and ketones. They showed a good activity in catalytic hydrosilylation of aldehydes and ketones by using (EtO)3SiH as a hydrogen source under mild conditions.
- Xue, Benjing,Sun, Hongjian,Li, Xiaoyan
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p. 52000 - 52006
(2015/06/25)
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- (Caffeine) (tetrahydroborato)zinc complex [Zn(BH4 )2 (caf)]: A new stable and efficient reducing agent
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In this context, (Caffeine)(tetrahydroborato)zinc complex as white stable reducing agents [Zn(BH4 )2 (caf)], has been prepared by complexation of one equimolar amounts of zinc tetrahydroborate and one equimolar amounts of caffeine at room temperature. Also, [Zn(BH4 )2 (caf) ]has been used for reduce of a variety of carbonyl compounds such as aldehydes, ketones, α, β-unsaturated carbonyl compounds, acyloins and a-diketones to their corresponding alcohols in excellent yields (90-95%). The reduction reactions have been completed in appropriate times (30-90 min) by using of 0.5-1 equivalents of [Zn(BH4 )2 (caf)] in CH3 CN at room temperature or under reflux conditions.
- Abdollahpour, Fatemeh,Setamdideh, Davood
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p. 1787 - 1792
(2016/01/25)
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- (Acridine)(tetrahydroborato)zinc complex [Zn(BH4)2(acr)]: A new stable and efficient reducing agent
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(Acridine)(tetrahydroborato)zinc complex[Zn(BH4)2(acr)] has been prepared by complexation of oneequimolar amounts of zinc tetrahydroborate and one equimolar amounts of acridine at room temperatureas gray stable reducing agents. Also, [Zn(BH4)2(acr)] has been used for reduce of different carbonyl compounds such as aldehydes, ketones, α, β-unsaturated carbonyl compounds, acyloins and a-diketones to their corresponding alcohols in excellent yields (85-95%). The reduction reactions have been carried outwithin 30-120 min by using of 0.5-1 equivalents of [Zn(BH4)2(acr)] in CH3CN at room temperature or under reflux conditions.
- Mohammadi, Sina,Setamdideh, Davood
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p. 2395 - 2399
(2016/02/27)
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- Imine Nitrogen Bridged Binuclear Nickel Complexes via N-H Bond Activation: Synthesis, Characterization, Unexpected C,N-Coupling Reaction, and Their Catalytic Application in Hydrosilylation of Aldehydes
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The reactions of NiMe2(PMe3)3 with 2,6-difluoroarylimines were explored. As a result, a series of binuclear nickel complexes (5-8, 11) were synthesized. Meanwhile, from the reactions of NiMe2(PMe3)3 with [2-CH3C6H4-C(=NH)-2,6-F2C6H3] (9) and [2,6-(CH3)2C6H3-C(=NH)-2,6-F2C6H3] (10), two unexpected C,N-coupling products (12 and 13) were obtained. It is believed that these coupling reactions underwent activation of the N-H and C-F bonds. The binuclear nickel complexes showed excellent catalytic activity in the hydrosilylation of aldehydes. The mechanism of the reaction was studied through stoichiometric reactions, and the double-(η2-Si-H)-NiII intermediate was detected by in situ 1H NMR spectroscopy, which may be the key point in the catalytic cycle.
- Wang, Lin,Sun, Hongjian,Li, Xiaoyan
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p. 5175 - 5182
(2015/11/09)
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- Synthesis of iron hydrides by selective C-F/C-H bond activation in fluoroarylimines and their applications in catalytic reduction reactions
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The reactions of Fe(PMe3)4 with different 2,6-diflurophenylarylimines 1-5 were explored. Fluoroarylimines 1-3, the aryl rings of which are substituted with electron-withdrawing groups, reacted with Fe(PMe3)4 to afford the C-H activation products 6-8. However, if the aryl rings of the fluoroarylimines were substituted with electron-donating groups, the iron hydrides 9 and 10 were obtained from the reactions of the fluoroarylimines with Fe(PMe3)4 through C-F bond activation. In a further study, silanes, especially triethoxysilane, were found to benefit the reactions and improve the yields of the hydridoiron complexes. The three-component reaction of Fe(PMe3)4, a fluoroarylimine, and a silane could also be utilized in reactions involving 2,6-(CH3)2C6H3-C(=NH)-2,6-F2C6H3 (13) and 2,6-F2C6H3-C(=NH)-C6F5 (16) to synthesize iron hydrides (15 and 18). The hydridoiron complexes could be utilized as efficient catalysts in the hydrosilylation of aldehydes and ketones. Furthermore, cinnamaldehydes were selectively reduced to the corresponding cinnamyl alcohols in high yields. The mechanism of the catalytic reduction reaction was studied extensively through operando IR spectroscopy.
- Wang, Lin,Sun, Hongjian,Li, Xiaoyan
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p. 2732 - 2743
(2015/06/22)
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- Synthesis and catalytic property of iron pincer complexes generated by Csp3-H activation
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When the diphosphinito PCP ligand (Ph2P(C6H 4))2CH2 (1) was treated with Fe(PMe 3)4 and FeMe2(PMe3)4, the Csp3-H activation products [(Ph2P(C 6H4))2CH]Fe(H)(PMe3)2 (2) and [(Ph2P(C6H4))(PhP(C6H 4)2)CH]Fe(PMe3)2 (3) were obtained at room temperature. The generation of product 3 underwent one C sp3-H and one Csp2-H bond activation process. The new iron hydride complex 2 showed good activity in the catalytic hydrosilylation of aldehydes and ketones by using (EtO)3SiH as the hydrogen source under mild conditions. Complexes 2 and 3 were characterized by spectroscopic methods and X-ray diffraction analysis.
- Zhao, Hua,Sun, Hongjian,Li, Xiaoyan
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p. 3535 - 3539
(2014/08/05)
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- Synthesis of structurally diverse diarylketones through the diarylmethyl sp3 C-H oxidation
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Under open-flask conditions, an efficient method to assemble a series of diversely functionalized diarylketones in the presence of commercially available NBS has been developed. Yields of up to 99% have been achieved employing diarylmethanes as starting material. Based on 18O-labeled experiment, the addition of stoichiometric water eventually leads to excellent yields in all carbonylation cases.
- He, Chao,Zhang, Xiaohui,Huang, Ruofeng,Pan, Jing,Li, Jiaqiang,Ling, Xuege,Xiong, Yan,Zhu, Xiangming
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supporting information
p. 4458 - 4462
(2014/08/05)
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- Metal-free, visible-light photoredox catalysis: Transformation of arylmethyl bromides to alcohols and aldehydes
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A mild, simple, and controllable metal-free photocatalytic system for the transformation of arylmethyl bromides to corresponding alcohols and aldehydes in high yields with visible-light irradiation has been achieved. Eosin Y was found to be an efficient promoter for this oxidative dehalogenation reaction under photo irradiation conditions.
- Li, Jian,Wang, Hongni,Liu, Li,Sun, Jiangtao
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p. 49974 - 49978
(2014/12/10)
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- Synthesis of stilbene, 1,4-distyrylbenzene and 4,4′-distyrylbiphenyl via Horner-Wadsworth-Emmons reaction in phase-transfer catalysis system
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Stilbenes, 1,4-distyrylbenzenes and 4,4′-distyrylbiphenyls were synthesized via Horner-Wadsworth-Emmons (HWE) reaction in liquid-liquid (LL) and solid-liquid (SL) phase transfer catalysis (PTC) systems. The effect of the side reaction, reactants and the third phase on the activity of HWE reaction were investigated. For aldehydes bearing electron-donating substitute, the yields were more than 90% and the products were all (E)-isomers in both PTC systems. The SL-PTC system was milder than LL-PTC system for HWE reaction due to the different mechanisms. The side reaction of aldehyde was similar to Cannizzaro reaction, whereas the molar ratio of benzoic acid to benzyl alcohol as the products was not 1:1. The limited third phase was discovered to exist in LL-PTC system. In SL-PTC system, the third phase could increase substantially the reaction rate. Moreover, the aqueous phase in LL-PTC system could be reused four times without sacrifice of the yield and reaction rate.
- Zhao, Qiangqiang,Sun, Jie,Liu, Baojiang,He, Jinxin
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p. 339 - 347
(2013/10/21)
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- Zn(BH4)2/2NaCl: A novel reducing system for efficient reduction of organic carbonyl compounds to their corresponding alcohols
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Zn(BH4)2/2NaCl, obtained by the reaction of ZnCl 2 and NaBH4 ,is a stable, efficient and selective reducing system in dry-THF. The Zn(BH4)2/2NaCl system (0.5-1 mmol) reduces a variety of carbonyl compounds to their corresponding alcohols in CH3CN at room temperature in high to excellent yields.
- Setamdideh, Davood,Khaledi, Leila
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p. 150 - 157
(2013/07/26)
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- NaBH4/DOWEX(R)50WX4: A convenient reducing system for fast and efficient reduction of carbonyl compounds to their corresponding alcohols
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The reduction of a variety of carbonyl compounds was efficiently carried out with NaBH4/ DOWEX(R)50WX4 system. The reactions were performed to give the corresponding alcohols derivatives in perfect yields in THF at room temperature. Reduction of acyloins and-diketones by this reducing system produced efficiently the corresponding vicinal diols. Also, the reduction of aldehydes over ketones has been accomplished successfully by this system. Regioselectivity of this system was also investigated with exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields.
- Setamdideh, Davood,Karimi, Zahra,Alipouramjad, Avat
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p. 590 - 596
(2013/10/22)
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- Zn(BH4)2/Al2O3: A new synthetic method for the efficient and convenient reduction of organic carbonyl compounds to their corresponding alcohols
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Zn(BH4)2 (0.5-2 mmol) in the presence of Al 2O3 (1 mmol) reduces a variety of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols. The reduction reactions were realized in THF at room temperature affording high to excellent yields of the products. The chemoselective reduction of aldehydes over ketones was successfully accomplished with this reducing system. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was successfully accomplished.
- Setamdideh, Davood,Khezri, Behrooz,Rahmatollahzadeh, Mehdi
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- Cyclometalated iridium complexes for transfer hydrogenation of carbonyl groups in water
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Cyclometalated iridium complexes are shown to be excellent catalysts for transfer hydrogenation of carbonyl compounds in water using formate as a hydrogen source. A wide range of ketones and aldehydes have been reduced at 0.05% catalyst loading with no need for any organic solvents. Solution pH is found to play a critical role, with acidic conditions needed for fast transfer hydrogenation.
- Wei, Yawen,Xue, Dong,Lei, Qian,Wang, Chao,Xiao, Jianliang
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supporting information
p. 629 - 634
(2013/04/10)
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- Direct deamination of primary amines by water to produce alcohols
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Just add water! The title reaction is catalyzed by an acridine-based pincer complex (1, see scheme). This one-step transformation uses water as the only reagent in the absence of additional bases, oxidants, or reductants. Cyclization of 1,4-diaminobutane and 1,6-diaminohexane catalyzed by 1 leads to the formation of pyrrolidine and azepane, respectively. Copyright
- Khusnutdinova, Julia R.,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 6269 - 6272
(2013/07/19)
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- Selective switchable iron-catalyzed hydrosilylation of carboxylic acids
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Selective reduction of carboxylic acids either to aldehydes or alcohols is achieved using a one pot procedure based on iron-catalyzed hydrosilylations. Using phenylsilane and (COD)Fe(CO)3 catalyst under UV-irradiation at rt, alcohols were obtained specifically in good yields, whereas aldehydes were selectively obtained using TMDS and (t-PBO)Fe(CO)3 catalyst under thermal activation.
- Misal Castro, Luis C.,Li, Haoquan,Sortais, Jean-Baptiste,Darcel, Christophe
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supporting information
p. 10514 - 10516,3
(2020/09/02)
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- Convenient reduction of carbonyl compounds to their corresponding alcohols with NaBH4/(NH4)2C2O4 system
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Sodium borohydride (0.4-1.5 equivalents) in the presence of ammonium oxalate (0.2 equivalents) reduces varieties of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β- unsaturated carbonyl compounds to their corresponding alcohols. Reduction reactions were carried out in acetonitrile in high to excellent yields of products. The chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was achieved successfully with this reducing system.
- Setamdideh, Davood,Ghahremani, Sahar
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experimental part
p. 91 - 97
(2012/07/14)
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- Mild and efficient reduction of organic carbonyl compounds to their corresponding alcohols with Zn(BH4)2 under protic condition
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Zn(BH4)2 (1-2 mmol) in wet THF or CH3CN reduces varieties of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α, β-unsaturated carbonyl compounds to their corresponding alcohols. Reduction reactions were carried out in wet THF at room temperature in high to excellent yields of products. The chemoselective reduction of aldehydes over ketones was accomplished successfully. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was accomplished successfully with this reducing system.
- Setamdideh, Davood,Khezri, Behrooz,Rahmatollahzadeh, Mehdi,Poramjad, Avat Ali
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experimental part
p. 3591 - 3596
(2012/07/28)
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- Rapid and efficient protection of alcohols and phenols, and deprotection of trimethylsilyl ethers catalyzed by a cerium-containing polyoxometalate
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Herein, we want to report a simple and convenient way for protection-deprotection of alcohols in the presence of ammonium decatungstocerate(IV) {(NH4)8[CeW10O 36]A·20H2O} as catalyst under ambient temperature in CH3CN. Using 0.002 mmol of the catalyst, various alcohols and phenols were transformed easily to the corresponding TMS ethers in excellent yields. In the second part, various TMS ethers were successfully converted to the parent hydroxyl compounds in the presence of the ammonium decatungstocerate(IV) catalyst.
- Yadollahi, Bahram,Mirkhani, Valiollah,Tangestaninejad, Shahram,Karimian, Davud
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experimental part
p. 83 - 86
(2012/06/18)
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- Wet SiO2 as a suitable media for fast and efficient reduction of carbonyl compounds with NABH3CN under solvent-free and acid-free conditions
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Reduction of carbonyl compounds such as aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones and acyloins was carried out readily with NaBH3CN in the presence of wet SiO2 as a neutral media. The reactions were performed at solvent-free conditions in oil bath (70-80 °C) or under microwave irradiation (240 W) to give the product alcohols in high to excellent yields. Regioselective 1,2-reduction of conjugated carbonyl compounds took place in a perfect selectivity without any side product formation.
- Kouhkan, Mehri,Zeynizadeh, Behzad
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experimental part
p. 2961 - 2966
(2012/04/17)
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- Microwave-assisted rapid and efficient deprotection and direct esterification and silylation of MOM and EOM ethers catalyzed by [Hmim][HSO 4] as a Bronsted acidic ionic liquid
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1-Methylimidazolium hydrogensulfate, [Hmim] [HSO4], a Bronsted acidic room temperature ionic liquid, is used as a catalyst and reaction medium for facile and ecofriendly deprotection of methoxymethyl (MOM) and ethoxymethyl (EOM) ethers to their corresponding alcohols under thermal conditions (Δ) and microwave irradiation (MW). Furthermore, one-pot interconversion to the respective acetates and trimethylsilyl (TMS) ethers was also achieved. Springer-Verlag 2010.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza,Mirjafari, Arsalan
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experimental part
p. 1083 - 1088
(2012/06/18)
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- Green and efficient procedure for the trimethylsilylation of hydroxy groups and their regeneration using sulfamic acid as recyclable catalyst
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Structurally diverse alcohols and phenols were efficiently transformed into their corresponding trimethylsilyl ethers with hexamethyldisilazane (HMDS) in the presence of catalytic amounts of sulfamic acid (SA) at room temperature under both acetonitrile and solvent-free conditions. Deprotection of these trimethylsilyl ethers to their parent alcohols and phenols was also achieved using this catalyst in water at room temperature. Copyright Taylor & Francis Group, LLC.
- Rostami, Amin,Ahmad-Jangi, Firoz,Zarebin, Mohammad Rezgar,Akradi, Jamal
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experimental part
p. 1500 - 1507
(2010/07/15)
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- Boric acid as cost-effective and recyclable catalyst for trimethylsilyl protection and deprotection of alcohols and phenols
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Boric acid has been used as a green, selective and recyclable catalyst for trimethysilylation of alcohols and phenols using hexamethyldisilazane in acetonitrile. Deprotection of trimethylsilyl ethers to their parent alcohols and phenols was also achieved using this catalyst in water at room temperature. The salient features of this methodology are cheap processing, mild acidity conditions, excellent yields of products and easy availability of the catalyst.
- Rostami, Amin,Akradi, Jamal,Ahmad-Jangi, Firoz
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experimental part
p. 1587 - 1592
(2010/11/04)
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- Synthesis of amides through the Cannizzaro-type reaction catalyzed by lanthanide chlorides
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Amidation of aldehydes with lithium amides through the LnCl3-catalyzed Cannizzaro-type reactions afforded a variety of amides in high yields. The electronic and steric effects on the reaction were investigated. The features of the economical ca
- Zhang, Lijun,Su, Shunpeng,Wu, Hongping,Wang, Shaowu
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supporting information; experimental part
p. 10022 - 10024
(2010/02/27)
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- H3PW12O40 - A selective, environmentally benign, and reusable catalyst for the preparation of methoxymethyl and ethoxymethyl ethers and their deprotections under mild conditions
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Different types of primary and secondary alcohols were efficiently transformed to their corresponding methoxymethyl (MOM) and ethoxymethyl (EOM) ethers in the presence of catalytic amounts of H3PW 12O40 at room temperature under solvent-free conditions. Selective protection of primary and secondary alcohols in the presence of phenols and tertiary alcohols was achieved by this method. Deprotection of these ethers to their parent alcohols was also performed using this catalyst in ethanol under reflux conditions. We have also found that primary and secondary MOM- and EOM-ethers are selectively deprotected in the presence of phenolic and tertiary ones, methyl and benzyl ethers, esters, and trimethylsilyl ethers by this catalyst. The notable advantages of this protocol are high yields, short reaction times, easy work-up, non-toxicity, easy availability and handling, eco-friendly, and reusability of the catalyst.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mirjafari, Arsalan
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p. 831 - 840
(2008/12/21)
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- Solvent-free oxidation of alcohols and mild catalytic deprotection of silyl ethers with poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulphonamide) and N,N,N′,N′-tetrabromobenzene-1,3-disulphonamide
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Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulphonamide) (PBBS) and N,N,N′,N′-tetrabromobenzene-1,3-disulphonamide (TBBDA) can be used for solvent-free oxidation of primary and secondary alcohols to the corresponding carbonyl compounds without over-oxidation, and efficient catalytic deprotection of various silyl ethers to hydroxyl groups in aprotic organic solvents under ambient conditions.
- Ghorbani-Vaghei, Ramin,Amiri, Mostafa,Chegny, Mahdieh,Veisi, Hojat
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- Mild and convenient method for reduction of carbonyl compounds with the NaBH4/charcoal system in wet THF
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The NaBH4/C (charcoal) system reduces a variety of carbonyl compounds such as aldehydes, ketones, acyloins and α-diketones to their corresponding alcohols in high to excellent yields. Reduction reactions were carried out in wet THF at r.t. In addition, regioselective 1,2-reduction of α,β-unsaturated aldehydes and ketones was achieved perfectly with this reducing system. By decreasing the amount of aprotic solvent, all reductions took place fast and efficiently under solid-gel condition.
- Setamdideh, Davood,Zeynizadeh, Behzad
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p. 1275 - 1281
(2008/09/18)
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- Cannizzaro-type disproportionation of aromatic aldehydes to amides and alcohols by using either a stoichiometric amount or a catalytic amount of lanthanide compounds
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Aromatic aldehydes can be directly converted to the corresponding amides and alcohols in good to excellent yields by the treatment of aromatic aldehydes with lithium amide LiN(SiMe3)2 in the presence of catalytic lanthanide chlorides LnCIs or by the treatment of aromatic aldehydes with a stoichiometric amount of lanthanide amides [(Me3Si)2N]3Ln(μ-Cl) Li(THF)3 at ambient temperature. The effects of solvents, substitutents on the phenyl ring, and lanthanide metals on the reaction have been examined. The mechanism of the disproportionation reaction was proposed based on the experimental results.
- Zhang, Lijun,Wang, Shaowu,Zhou, Shuangliu,Yang, Gaosheng,Sheng, Enhong
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p. 3149 - 3153
(2007/10/03)
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- The pinacol coupling of aromatic aldehydes in ethyl acetate mediated by TiCl4-Al
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Titanium tetrachloride in ethyl acetate can be reduced by Al powder to the corresponding low valent titanium complexes, which can mediate the conversion of some aromatic aldehydes into the corresponding pinacols in 23-93% yields within 25-120 min under stirring at r.t. When N,N,N′,N′- tetramethylethylene diamine (TMEDA) is added, the diastereoselectivities of the reactions are improved.
- Wang, Shu-Xiang,Wang, Ke,Liu, Guo-Biao,Cui, Jin,Li, Ji-Tai
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p. 348 - 350
(2007/10/03)
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