- Bio-inspired asymmetric aldehyde arylations catalyzed by rhodium-cyclodextrin self-inclusion complexes
-
Transition-metal catalysts are powerful tools for carbon-carbon bond-forming reactions that are difficult to achieve using native enzymes. Enzymes that exhibit inherent selectivities and reactivities through host-guest interactions have inspired widesprea
- Asahi, Kaoru,Fujiwara, Shin-Ichi,Iwasaki, Takanori,Kambe, Nobuaki,Takahashi, Ryota,Tsuda, Susumu,Ueda, Ryoji,Yamauchi, Hiroki
-
supporting information
p. 801 - 807
(2022/02/03)
-
- Preparation method of cetirizine impurity C
-
The present invention relates to the field of pharmaceutical chemical technology, specifically, to a method for preparing cetirizine impurity C. The method is to prepare the key intermediate 4-{(2-chlorophenyl)phenyl) directly with hydroxyethylpiperazine
- -
-
Paragraph 0052-0055; 0068-0070; 0075-0077
(2022/01/10)
-
- A Direct Br?nsted Acid-Catalyzed Azidation of Benzhydrols and Carbohydrates
-
Benzhydryl alcohols were converted into their corresponding diarylazidomethane analogues using azidotrimethylsilane (TMSN3) in the presence of a catalytic amount of a Br?nsted acid HBF4·OEt2. The azidation reactions proceeded in high yields and demonstrated excellent functional group tolerance to electron-donating and electron-withdrawing substituents. In addition, a range of unprotected functional groups including amine, amide, aldehyde and alcohol were well-tolerated. Furthermore, this methodology was successfully applied to carbohydrates for the preparation of the corresponding azide derivatives.
- Regier, Jeffery,Maillet, Robert,Bolshan, Yuri
-
p. 2390 - 2396
(2019/04/14)
-
- 4-Methyltetrahydropyran (4-MeTHP): Application as an Organic Reaction Solvent
-
4-Methyltetrahydropyran (4-MeTHP) is a hydrophobic cyclic ether with potential for industrial applications. We herein report, for the first time, a comprehensive study on the performance of 4-MeTHP as an organic reaction solvent. Its broad application to organic reactions includes radical, Grignard, Wittig, organometallic, halogen-metal exchange, reduction, oxidation, epoxidation, amidation, esterification, metathesis, and other miscellaneous organic reactions. This breadth suggests 4-MeTHP can serve as a substitute for conventional ethers and harmful halogenated solvents. However, 4-MeTHP was found incompatible with strong Lewis acids, and the C?O bond was readily cleaved by treatment with BBr3. Moreover, the radical-based degradation pathways of 4-MeTHP, THP and 2-MeTHF were elucidated on the basis of GC-MS analyses. The data reported herein is anticipated to be useful for a broad range of synthetic chemists, especially industrial process chemists, when selecting the reaction solvent with green chemistry perspectives.
- Kobayashi, Shoji,Tamura, Tomoki,Yoshimoto, Saki,Kawakami, Takashi,Masuyama, Araki
-
p. 3921 - 3937
(2019/11/11)
-
- Iodide as a Nucleophilic Trigger in Aryne Three-Component Coupling for the Synthesis of 2-Iodobenzyl Alcohols
-
The synthetic potential of KI as the iodide source in aryne three-component coupling has been demonstrated using aldehydes as the third component. This mild and transition-metal-free coupling reaction allowed the straightforward synthesis of 2-iodobenzyl alcohols in moderate to good yields with good functional group compatibility. Moreover, KBr and KCl could be used as the nucleophilic trigger in this aryne multicomponent coupling (MCC) and N-methylisatin and CO2 could be used as the electrophilic third components.
- Bhattacharjee, Subrata,Guin, Avishek,Gaykar, Rahul N.,Biju, Akkattu T.
-
supporting information
p. 4383 - 4387
(2019/06/08)
-
- Diaryl hydroxylamines as pan or dual inhibitors of indoleamine 2,3-dioxygenase-1, indoleamine 2,3-dioxygenase-2 and tryptophan dioxygenase
-
Tryptophan (Trp) catabolizing enzymes play an important and complex role in the development of cancer. Significant evidence implicates them in a range of inflammatory and immunosuppressive activities. Whereas inhibitors of indoleamine 2,3-dioxygenase-1 (IDO1) have been reported and analyzed in the clinic, fewer inhibitors have been described for tryptophan dioxygenase (TDO) and indoleamine 2,3-dioxygenase-2 (IDO2) which also have been implicated more recently in cancer, inflammation and immune control. Consequently the development of dual or pan inhibitors of these Trp catabolizing enzymes may represent a therapeutically important area of research. This is the first report to describe the development of dual and pan inhibitors of IDO1, TDO and IDO2.
- Winters, Maria,DuHadaway, James B.,Pham, Khoa N.,Lewis-Ballester, Ariel,Badir, Shorouk,Wai, Jenny,Sheikh, Eesha,Yeh, Syun-Ru,Prendergast, George C.,Muller, Alexander J.,Malachowski, William P.
-
supporting information
p. 455 - 464
(2018/11/25)
-
- Employing Arynes for the Generation of Aryl Anion Equivalents and Subsequent Reaction with Aldehydes
-
Arynes are highly reactive intermediates, which are utilized for the electrophilic arylation of various X-H bonds (X = O, N, S etc.). Herein, a new synthetic strategy is demonstrated, where arynes are converted into aryl anion equivalents by treatment with phosphines and a base. The addition of phosphines to arynes form the phosphonium salts, which in the presence of a carbonate base generates the aryl anion equivalent. Subsequent addition of the aryl anions with aldehydes afforded the secondary alcohols.
- Gaykar, Rahul N.,Bhunia, Anup,Biju, Akkattu T.
-
p. 11333 - 11340
(2018/07/21)
-
- And its manufacturing method hydroxytriarylamine compd., and its use
-
PROBLEM TO BE SOLVED: To provide an effective material in an organic EL element using a phosphorescent material. SOLUTION: An amine compound expressed by general formula (1) is used in at least one layer among an emission layer, a hole-transport layer and a hole-injection layer, where in formula (1), the rings A, B and C each represents an aromatic ring or a heteroaromatic ring; R1, R2, R3and R4each represents a hydrogen atom, aliphatic hydrocarbon group, alkoxy group, cyano group, aryl group, aryloxy group or heteroaryl group; and Ar1and Ar2each represents an aryl group or heteroaryl group which may have substituents. COPYRIGHT: (C)2012,JPOandINPIT
- -
-
Paragraph 0116; 0117
(2016/11/17)
-
- Synthetic method of diaryl methanol compound
-
The invention discloses a synthetic method of a diaryl methanol compound. Compared with a reported method for obtaining the diaryl methanol compound through catalytic reduction by taking diaryl ketone as an initial raw material, the method is characterized by taking substituted benzyl bromide and substituted phenylboronic acid which are cheap and easy to obtain as initial raw materials, reacting for 4 hours in an alkaline solution, water or a mixed solvent of the water and an organic solvent under room temperature in air, and carrying out simple separation and purification operation, thus obtaining a pure product. A catalyst adopted in the method is a palladium compound/an in-situ catalytic system prepared from phosphorus- and oxygen-containing carboxylic acids ligands, the catalytic system is cheap in price, high in catalytic activity and good in selectivity and is stable in the air and a water solution, the diaryl methanol compound is compounded through a method of catalyzing the substituted benzyl bromide and the substituted phenylboronic acid and a 'one-pot reaction method' of hydrogen peroxide, the reaction steps are less, after-treatment is simple, the product is easy to separate and purify, the yield is high, and the mixed solvent is prepared from cheap and easy-to-obtain water and the organic solvent, so that the environment is not polluted, and environment protection is realized.
- -
-
Paragraph 0062-0064
(2017/04/03)
-
- Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
-
By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
- Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
-
supporting information
p. 15058 - 15068
(2016/10/11)
-
- Newly synthesized furanoside-based NHC ligands for the arylation of aldehydes
-
New furanoside-based NHC precursor salts (2) were synthesized using amino alcohols from the chloralose derivatives of glucose (a), galactose (b), and mannose (c). The novel compounds were fully characterized by 1H NMR, 13C NMR, and elemental analyses. The catalytic activities of these salts were tested in the arylation of aldehydes as catalysts that were generated in situ from [RhCl(COD)]2. In addition, 2a was converted to the rhodium complex 3a in order to compare the results obtained in situ. The newly synthesized compounds were very efficient in terms of yield; nevertheless they did not exhibit a chiral induction.
- Denizalti, Serpil,?etin Telli, Fatma,Yildiran, Selin,Salman, Azize Ye?im,?etinkaya, Bekir
-
p. 689 - 697
(2016/11/09)
-
- An unusual chemoselective oxidation strategy by an unprecedented exploration of an electrophilic center of DMSO: A new facet to classical DMSO oxidation
-
A conceptually new dimethyl sulfoxide (DMSO) based oxidation process without the use of any activator has been demonstrated for the oxidation of active methylenes and benzhydrols. The developed protocol utilizes the electrophilic center of DMSO for oxidation, which was unexplored before. Mechanistic investigation has confirmed that the source of oxygen is DMSO.
- Chebolu, Rajesh,Bahuguna, Ashish,Sharma, Reena,Mishra, Vivek Kumar,Ravikumar
-
supporting information
p. 15438 - 15441
(2015/10/20)
-
- The carbonyl group tuned electron-deficient phosphorus ligands and their application in Rhodium catalyzed arylation to aldehydes
-
Acylphosphines, which could be efficiently prepared from acid chlorides and secondary phosphines, were developed as a type of carbonyl group tuned electron-deficient phosphorus ligand. They were found to be a kind of efficient ligand in Rhodium catalyzed arylation to aldehydes through accelerating the transmetalation process. Chiral acylphosphine ligands could be generated from carboxylic acids bearing the chiral framework correspondingly.
- Yang, Jiefang,Chen, Xingyu,Wang, Zhiqian
-
supporting information
p. 5673 - 5675
(2015/09/15)
-
- Recyclable and reusable Pd(OAc)2/P(1-Nap)3/[bmim][PF6]/H2O system for the addition of arylboronic acids to aldehydes
-
A stable and efficient Pd(OAc)2/P(1-Nap)3[tri(1-naphthyl)phosphine] catalytic system for the addition of arylboronic acids to aldehydes has been developed. In the presence of Pd(OAc)2 and P(1-Nap)3, the addition reaction of arylboronic acids with aldehydes was carried out smoothly at 65 °C to give a variety of carbinol derivatives in good to excellent yields using a mixture of [bmim][PF6] and water as the solvent. The isolation of the products was readily performed by the extraction with diethyl ether, and the Pd(OAc)2/P(1-Nap)3/[bmim][PF6]/H2O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile THF or toluene as solvent but also solves the basic problem of palladium catalyst and these phosphine ligand reuse.
- Zhao, Hong,Cheng, Mingzhu,Zhang, Tinli,Cai, Mingzhong
-
-
- From in vitro to in cellulo: Structure-activity relationship of (2-nitrophenyl)methanol derivatives as inhibitors of PqsD in Pseudomonas aeruginosa
-
Recent studies have shown that compounds based on a (2-nitrophenyl)methanol scaffold are promising inhibitors of PqsD, a key enzyme of signal molecule biosynthesis in the cell-to-cell communication of Pseudomonas aeruginosa. The most promising molecule displayed anti-biofilm activity and a tight-binding mode of action. Herein, we report on the convenient synthesis and biochemical evaluation of a comprehensive series of (2-nitrophenyl)methanol derivatives. The in vitro potency of these inhibitors against recombinant PqsD as well as the effect of selected compounds on the production of the signal molecules HHQ and PQS in P. aeruginosa were examined. The gathered data allowed the establishment of a structure-activity relationship, which was used to design fluorescent inhibitors, and finally, led to the discovery of (2-nitrophenyl)methanol derivatives with improved in cellulo efficacy providing new perspectives towards the application of PqsD inhibitors as anti-infectives. This journal is the Partner Organisations 2014.
- Storz, Michael P.,Allegretta, Giuseppe,Kirsch, Benjamin,Empting, Martin,Hartmann, Rolf W.
-
supporting information
p. 6094 - 6104
(2014/08/05)
-
- Chelating alkoxy NHC-Rh(I) complexes and their applications in the arylation of aldehydes
-
In this study, new rhodium(I) complexes (5 and 6) have been prepared by the reaction of [RhCl(COD)]2 with a series of imidazolium salts (3 and 4), which were obtained from a chiral amino alcohol. The catalytic activities of these complexes were tested in the arylation of aldehydes. It was found that the synthesized rhodium complexes were highly effective catalysts for the arylation of aldehydes in short reaction times (5 min, TOF = 1193 h -1). However, the obtained ee values (up to 32% ee) remained low. We have proposed a mechanism for the arylation reaction of aldehydes, which is confirmed via 19F NMR spectroscopy.
- Denizalti, Serpil,Türkmen, Hayati,?etinkaya, Bekir
-
supporting information
p. 4129 - 4132
(2014/07/22)
-
- Bu4N+ alkoxide-initiated/autocatalytic addition reactions with organotrimethylsilanes
-
The use of Me3SiO-/Bu4N+ as a general activator of organotrimethylsilanes for addition reactions has been established. The broad scope of the method offers trimethylsilanes (including acetate, allyl, propargyl, benzyl, dithiane, heteroaryl, and aryl derivatives) as bench-stable organometallics that can be readily utilized as carbanion equivalents for synthesis. Reactions are achieved at rt without the requirement of specialized precautions that are commonplace for other organometallics.
- Das, Manas,O'Shea, Donal F.
-
p. 5595 - 5607
(2014/07/08)
-
- Highly efficient homogeneous and heterogenized ruthenium catalysts for transfer hydrogenation of carbonyl compounds
-
[Ru(acac)2(CH3CN)2] was synthesized from [Ru(acac)3] by refluxing it with zinc powder in ethanol-acetonitrile mixture. The prepared catalyst was characterized by FT-IR, 1H and 13C NMR techniques. The silica supported catalyst ('SiO 2'-NH2-RuII) was prepared by stirring [Ru(acac)2(CH3CN)2] with 'SiO 2'-NH2 in a 1:1 mixture of CH2Cl 2-toluene for 3 days at room temperature. It was characterized by FT-IR, SEM, solid state NMR, ICP and BET surface area methods. The transfer hydrogenation reaction of carbonyl compounds was carried out separately using [Ru(acac)2(CH3CN)2] and 'SiO 2'-NH2-RuII as catalysts. The reaction conditions were optimized with different solvents, bases, catalyst amounts and temperatures using acetophenone as a model system. The scope of the reaction was extended to various substituted aryl ketones including heteroaryl ketones. This journal is the Partner Organisations 2014.
- Ganesamoorthy,Jerome,Shanmugasundaram,Karvembu
-
p. 27955 - 27962
(2014/07/21)
-
- Direct electrosynthesis of ketones from benzylic methylenes by electrooxidative C-H activation
-
Electrify your chemistry! Direct electrosynthesis of ketones from benzylic methylenes in an undivided cell was realized in moderate to good yields (see scheme). In this electrosynthesis, electrons instead of conventional oxidants and catalysts are employed to make the reaction environmentally benign. Moreover, the reaction intermediate radical was detected by ESR spectroscopy and the reaction mechanism was clarified.
- Meng, Li,Su, Jihu,Zha, Zhenggen,Zhang, Li,Zhang, Zhenlei,Wang, Zhiyong
-
supporting information
p. 5542 - 5545
(2013/05/23)
-
- (N -Phosphinoamidinate)Iron pre-catalysts for the room temperature hydrosilylation of carbonyl compounds with broad substrate scope at low loadings
-
The synthesis and structural characterization of three-coordinate iron(II) and cobalt(II) complexes supported by new N-phosphinoamidinate ligands is reported, along with the successful application of these complexes as precatalysts for the challenging room-temperature hydrosilylation of carbonyl compounds to afford alcohols upon workup. Under the rigorous screening conditions employed (0.015 mol % Fe) for the reduction of acetophenone, the well-defined iron(II) amido precatalyst 2b, featuring bulky N-2,6- diisopropylphenyl and di-tert-butylphosphino moieties within the N-phosphinoamidinate ligand, exhibited exceptional catalytic performance. Further experimentation revealed that the yield achieved in the hydrosilylation of acetophenone employing 2b was unaltered when conducting reactions in the absence of light, in the presence of excess mercury, or under solvent-free conditions. Notably, precatalyst 2b was found to exhibit the broadest substrate scope reported to date for such room-temperature iron-catalyzed carbonyl hydrosilylations en route to alcohols, enabling the chemoselective reduction of structurally diverse aldehydes and ketones, as well as for the first time esters, at remarkably low loadings (0.01-1.0 mol % Fe) and using only 1 equiv of phenylsilane reductant.
- Ruddy, Adam J.,Kelly, Colin M.,Crawford, Sarah M.,Wheaton, Craig A.,Sydora, Orson L.,Small, Brooke L.,Stradiotto, Mark,Turculet, Laura
-
supporting information
p. 5581 - 5588
(2013/11/06)
-
- Microwave-assisted nickel(II) acetylacetonate-catalyzed arylation of aldehydes with arylboronic acids
-
Applying sealed vessel microwave heating at 180 °C in toluene the arylation of aromatic and aliphatic aldehydes with arylboronic acids using 1-2 mol % of Ni(acac)2 as a catalyst can be performed efficiently within 10-30 min providing the desired diarylmethanols or benzyl alcohols in good yields.
- Chen, Wen,Baghbanzadeh, Mostafa,Kappe, C. Oliver
-
experimental part
p. 1677 - 1679
(2011/04/25)
-
- Synthesis, antibacterial and antifungal activities of bifonazole derivatives
-
Two series of chlorinated benzhydryl imidazole and triazole derivatives were synthesized and tested in vitro against representative strains of potent pathogenic bacteria (Staphylococcus aureus CIP 4.83, Escherichia hirae CIP 5855, Pseudomonas aeruginosa CIP 82118, Escherichia coli CIP 53126) and fungi (Aspergillus niger IP 1431.83, Candida albicans IP 48.72, Candida krusei IP 208.52, Trichophython rubrum IP 1657.86). Most of these compounds were devoid of any antimicrobial activity, but several of them inhibited T. rubrum with MIC values in the range of 0.125 to 32 μg/mL, similar or superior to those of bifonazole and clotrimazole, used as standard controls. The replacement of the imidazole ring with a triazole moiety in these compounds led to derivatives with less antifungal activity. A preliminary SAR was undertaken on the effect of the number and the position of chlorine atoms on the distribution of negative charge on the surface of some compounds on antifungal activity. Copyright
- El Hage, Salome,Lajoie, Barbora,Feuillolay, Catherine,Roques, Christine,Baziard, Genevieve
-
experimental part
p. 402 - 410
(2012/01/11)
-
- Structure-activity relationships of diphenylpiperazine N-type calcium channel inhibitors
-
A novel series of compounds derived from the previously reported N-type calcium channel blocker NP118809 (1-(4-benzhydrylpiperazin-1-yl)-3,3-diphenylpropan-1-one) is described. Extensive SAR studies resulted in compounds with IC50 values in the range of 10-150 nM and selectivity over the L-type channels up to nearly 1200-fold. Orally administered compounds 5 and 21 exhibited both anti-allodynic and anti-hyperalgesic activity in the spinal nerve ligation model of neuropathic pain.
- Pajouhesh, Hassan,Feng, Zhong-Ping,Ding, Yanbing,Zhang, Lingyun,Pajouhesh, Hossein,Morrison, Jerrie-Lynn,Belardetti, Francesco,Tringham, Elizabeth,Simonson, Eric,Vanderah, Todd W.,Porreca, Frank,Zamponi, Gerald W.,Mitscher, Lester A.,Snutch, Terrance P.
-
scheme or table
p. 1378 - 1383
(2010/07/06)
-
- MgCl2-accelerated addition of functionalized organozinc reagents to aldehydes, ketones, and carbon dioxide
-
Figure Presented Pump it up! The sluggish reactivity of organozinc reagents in additions to aldehydes, ketones, and CO2 can be increased by MgCl2, which is usually generated in the preparation of the zinc reagent. The direct reaction with CO2, in particular, opens an expeditious route to phenylacetic acid derivatives, as demonstrated in a short synthesis of ibuprofen (see scheme).
- Metzger, Albrecht,Bernhardt, Sebastian,Manolikakes, Georg,Knochel, Paul
-
supporting information; experimental part
p. 4665 - 4668
(2010/08/19)
-
- Synthesis and anticonvulsant activity of some cinnamylpiperazine derivatives
-
A series of cinnamylpiperazine derivatives was synthesized using different benzophenone as starting material. The structures of the compounds were proved by their IR, 1H-NMR spectroscopic data and mass spectra data. The anticonvulsant activities of these compounds were evaluated with maximal electroshock (MES) test and rotarod test with intraperitoneal injection on KunMing mice. Among all the flunarizine analogues, no one exhibited better anticonvulsant activity than flunarizine. Flunarizine (4i) exhibited anticonvulsant activity with ED50 of 38.1 mg/kg, TD50 of 164.3 mg/kg and PI of 4.3 through administration intraperitoneal, and with ED50 of 56.8 mg/kg, TD50 of 456.3 mg/kg and PI of 8.0 through oral administration.
- Hu, Chuan,Sun, Zhi-Gang,Wei, Cheng-Xi,Quan, Zhe-Shan
-
scheme or table
p. 661 - 664
(2011/11/29)
-
- A metal-free catalytic system for the oxidation of benzylic methylenes and primary amines under solvent-free conditions
-
Iodine-pyridine-tert-butylhydroperoxide is developed as a green and efficient catalytic system for the oxidation of benzylic methylenes to ketones and primary amines to nitriles. The reaction conditions are quite mild and environmentally benign, no transition metals, organic solvents or hazard reagents being needed. The oxidation of benzylic methylenes gave the corresponding ketones in excellent yields with complete chemoselectivity, while the oxidation of primary amines was complete in several minutes, affording various nitriles in moderate to good yields.
- Zhang, Jintang,Wang, Zhentao,Wang, Ye,Wan, Changfeng,Zheng, Xiaoqi,Wang, Zhiyong
-
supporting information; scheme or table
p. 1973 - 1978
(2010/06/15)
-
- A new route to acyclic diaminocarbenes via lithium-halogen exchange
-
A lithium - halogen exchange route has been developed to generate acyclic diaminocarbenes (ADC) from chloroamidinium salts. Convenient access to various ADC complexes (B, Rh, lr, Pd) stems from a one-pot transmetalation protocol. Formation of a carbenoid species is suggested by 1D and 2D NMR studies with a 13C-labeled chloroamidinium precursor and also by X-ray structures of transition metal-carbene complexes. Rh-ADC complex 4 is an effective catalyst for the 1,2-addition of aryl boronic acids to aryl aldehydes.
- Snead, David R.,Ghiviriga, Ion,Abboud, Khalil A.,Hong, Sukwon
-
supporting information; experimental part
p. 3274 - 3277
(2009/12/01)
-
- Highly efficient and facile aryl transfer to aldehydes using ArB(OH) 2-GaMe3
-
A rapid and efficient procedure for the synthesis of diarylmethanols has successfully been achieved by the aryl transfer to aldehydes using the ArB(OH)2-GaMe3 combined systems in excellent yields (up to 98%) at room temperature. Georg Thieme Verlag Stuttgart.
- Jia, Xuefeng,Fang, Ling,Lin, Aijun,Pan, Yi,Zhu, Chengjian
-
body text
p. 495 - 499
(2009/09/08)
-
- Generation and suppression of 3-/4-functionalized benzynes using zinc ate base (TMP-Zn-ate): New approaches to multisubstituted benzenes
-
We present full details of our new methods for preparing functionalized benzynes with lithium di-alkyl(2,2,6,6-tetramethylpiperidino)zincate (R 2Zn(TMP)Li) through deprotonative zincation as a key reaction. In this system, by choosing appropriate ligands for the zincate, either regioselective zincation of functionalized haloaromatics or the generation of substituted benzynes can be controlled in good yields with excellent chemoselectivity, using the same substrate. Zincation with tBu 2Zn(TMP)Li followed by electrophilic trapping or zincation with Me2Zn(TMP)Li followed by nucleophilic or diene trapping is shown to be a powerful tool for the chemoselective preparation of 1,2,3-/1,2,4- trisubstituted benzene derivatives. These methods offer far greater generality than previous methods for the synthesis of multifunctionalized benzenes. Computational/theoretical studies of the reaction mechanism of this unique benzyne formation indicated that preferential coordination of the dialkylzinc moiety of zincate to halogen is the reason for the reduced activation energy of the elimination, that is, for the formation of the benzyne. The role of the ligands on Zn in accelerating/decelerating the elimination is also discussed.
- Uchiyama, Masanobu,Kobayashi, Yuri,Furuyama, Taniyuki,Nakamura, Shinji,Kajihara, Yumiko,Miyoshi, Tomoko,Sakamoto, Takao,Kondo, Yoshinori,Morokuma, Keiji
-
p. 472 - 480
(2008/10/09)
-
- Development of highly chemoselective bulky zincate complex, tBu 4ZnLi2: Design, structure, and practical applications in small-/macromolecular synthesis
-
We present full details of the unique reactivities of the newly developed dianion-type bulky zincate, dilithium tetra-ferf-butylzincate (tBu 4ZnLi2). With this reagent, halogen-zinc exchange reaction of variously functionalized haloaromatics and anionic polymerization of N-isopropylacrylamide (NIPAm)/styrene with excellent chemoselectivity were realized. Halogen-zinc exchange reaction followed by electrophilic trapping with propargyl bromide provided a convenient route to functionalized phenylallenes, particularly those with electrophilic functional groups (such as cyano, amide and halogens). Spectral and computational studies of the structure in the gas and liquid phases indicated extraordinary stabilization of this dianion-type zincate by its bulky ligands.
- Furayama, Taniyuki,Yonehara, Mitsuhiro,Arimoto, Sho,Kobayashi, Minoru,Matsumoto, Yotaro,Uchiyama, Masanobu
-
supporting information; experimental part
p. 10348 - 10356
(2009/10/10)
-
- Palladium-catalyzed 1,2-addition of potassium aryl- and alkenyltrifluoroborates to aldehydes using thioether-imidazolinium carbene ligands
-
(Chemical Equation Presented) Palladium-catalyzed 1,2-addition of potassium aryl- and alkenyltrifluoroborates to aldehydes using thioether- imidazolinium carbene ligands proceeded readily under aqueous conditions. This process tolerated a diverse range of potassium trifluoroborate salts and aldehydes, giving a variety of carbinol derivatives with good to excellent yields.
- Kuriyama, Masami,Shimazawa, Rumiko,Enomoto, Terumichi,Shirai, Ryuichi
-
p. 6939 - 6942
(2008/12/22)
-
- Cyclopalladated complexes catalyzed addition of arylboronic acids to aldehydes in neat water
-
Cyclopalladated ferrocenylimine complexes gave high yields for the addition of arylboronic acids with aldehydes in neat water using a weak acid as additive.
- Yu, Ajuan,Cheng, Baoli,Wu, Yangjie,Li, Jingya,Wei, Kun
-
p. 5405 - 5407
(2008/12/21)
-
- Rapid ketone transfer hydrogenation by employing simple, in situ prepared iridium(I) precatalysts supported by "non-N-H" P,N ligands
-
The catalytic utility in ketone transfer hydrogenation (TH) of the preformed complexes [Ir(cod)(κ2-2-NMe2-3-PiPr 2-indene)]+X- ([2a]+X-; X: PF6, BF4, and OTf; cod: η4-1,5- cyclooctadiene; OTf: trifluoromethanesulfonate), [Ir(cod)(κ2-1- PiPr2-2-NMe2-indene)]+OTf- ([2b]+OTf-), [Ir-(cod)(κ2-2-NMe 2-3-PiPr2-indenide)] (3), and [Ir(cod) (κ2-o-tBu2P-C6H4-NMe 2)]+ PF6- ([4]+PF 6-), as well as of related mixtures prepared from [{IrCl(cod)}2] and various P,N-substituted indene or phenylene ligands, was examined. Whereas [2a]+X-, [2b] +OTf-, 3, and related in situ prepared Ir catalysts derived from P,N-indenes proved to be generally effective in mediating the reduction of acetophenone to 1-phenylethanol in basic iPrOH at reflux (0.1 mol% Ir; 81-99% conversion) in a preliminary catalytic survey, the structurally related Ir catalysts prepared from (o-R2P-C6H 4)NMe2 (R: Ph, iPr, or tBu) were observed to outperform the corresponding P,N-indene ligands under similar conditions. In the course of such studies, it was observed that alteration of the substituents at the donor fragments of the supporting P,N ligand had a pronounced influence on the catalytic performance of the derived catalysts, with ligands featuring bulky dialkylphosphino donors proving to be the most effective. Notably, the crystallographically characterized complex [4]+PF6 -, either preformed or prepared in situ from a mixture of [{IrCl-(cod)}2], NaPF6, and (o-tBu2P-C 6H4)NMe2, proved to be highly effective in mediating the catalytic transfer hydrogenation (TH) of ketones in basic iPrOH, with near quantitative conversions for a range of alkyl and/or aryl ketones and with very high turnover-frequency values (up to 230000 h-1 at > 50% conversion); this thereby enabled the use of Ir loadings ranging from 0.1 to 0.004 mol %. Catalyst mixtures prepared from [{IrCl-(cod)}2], NaPF6, and the chiral (αS,αS)-1,1'-bis[α- (dimethylamino)benzyl]-(R,R)-2,2'-bis(dicyclohexylphosphino)-ferrocene (Cy-Mandyphos) ligand proved capable of mediating the asymmetric TH of aryl alkyl ketones, including that of the hindered substrate 2,2- dimethylpropiophenone with an efficiency (0.5 mol % Ir; 95% conversion, 95% ee) not documented previously in TH chemistry.
- Lundgren, Rylan J.,Stradiotto, Mark
-
experimental part
p. 10388 - 10395
(2009/11/30)
-
- InCl3/Al mediated pinacol coupling reactions of aldehydes and?ketones in aqueous media
-
A systematic work on the homo-pinacol coupling reactions of benzophenones, aldehydes, and acetophenones in aqueous media with InCl3/Al is described for the first time, in which various 1,2-diols are obtained in moderate to good yields.
- Wang, Chunyan,Pan, Yuanjiang,Wu, Anxin
-
p. 429 - 434
(2007/10/03)
-
- Remarkably efficient enantioselective titanium(IV)-(R)-H 8-BINOLate catalyst for arylations to aldehydes by triaryl(tetrahydrofuran)aluminum reagents
-
Novel asymmetric triarylaluminum AlAr3(THF) additions to aldehydes catalyzed by 10 mol % of the titanium(IV) complex of (R)-H8-BINOL ligand are reported. The catalytic system is extremely efficient with reactions completing within 10 min. The system applies to the most diversified aldehydes to date, and more than 20 aldehydes were examined to afford diarylmethanols having an electron-donating or an electron-withdrawing group at the 2-, 3-, or 4-position on the aryl moiety, linear or branched 1-aryl aliphatic alcohols, aryl furyl methanols, 1-aryl allylic alcohols, and, especially, 1-aryl propargylic alcohols in excellent enantioselectivities of ≥90% ee, except for the case of 1-naphthyl addition to benzaldehyde. Noteworthily, diarylmethanols in both R- and S-configurations can be obtained. Copyright
- Wu, Kuo-Hui,Gau, Han-Mou
-
p. 14808 - 14809
(2008/02/09)
-
- Use of cheaper metal than Rh, CHCl3-free Pd catalyst, in 1,2-addition of aromatic aldehydes with arylboronic acids
-
Pd(OAc)2-(±)-tol-BINAP-catalyzed arylation reaction of aromatic aldehydes with arylboronic acids in the absence of CHCl3 is described.
- Suzuki, Kiyoto,Arao, Takafumi,Ishii, Satoru,Maeda, Yuka,Kondo, Kazuhiro,Aoyama, Toyohiko
-
p. 5789 - 5792
(2007/10/03)
-
- Asymmetric induction during electron transfer mediated photoreduction of carbonyl compounds: Role of zeolites
-
Photochemistry of 17 aryl alkyl ketones included within cation exchanged zeolites has been examined. In solution five of the 17 ketones undergo intramolecular hydrogen abstraction reaction even in the presence of a chiral amine and the rest are photoreduced to the corresponding alcohol. Within zeolites all 17 ketones yielded in presence of a chiral amine, the corresponding alcohol as the major product. When a chiral amine was used as the coadsorbent within alkali ion exchanged zeolites, enantiomerically enriched alcohol was formed in all cases. The best chiral induction was obtained with phenyl cyclohexyl ketone (enantiomeric excess: 68%). 1H-13C Cross Polarization Magic Angle Spinning (CP-MAS) experiments, with a model ketone (perdeuterated acetophenone) and chiral amine (pseudoephedrine) included within MY zeolites, suggested that the cation brings the reactant and the chiral amine closer. The role of the cation in such a process is also revealed by the computation results. The results presented here highlight the importance of a supramolecular structure in forcing a closer interaction between a reactant and a chiral inductor that could be used to achieve asymmetric induction in photoproducts. The Royal Society of Chemistry 2006.
- Shailaja,Kaanumalle, Lakshmi S.,Sivasubramanian, Karthikeyan,Natarajan, Arunkumar,Ponchot, Keith J.,Pradhan, Ajit,Ramamurthy
-
p. 1561 - 1571
(2008/02/03)
-
- BENZENE DERIVATIVES,PROCESS FOR PREPARING THE SAME AND USE THEREOF
-
Novel benzene derivatives represented by the formula (I) : wherein R1, R4 and R6 each independently represents a hydrogen atom, a halogen atom or a hydrocarbon group, R2 represents a hydrocarbon group or a heterocyclic group, R3 represents a hydrocarbon group, NR7'R7 or OR8 (wherein R7' represents a hydrogen atom or a hydrocarbon group, R7 represents a non-aromatic group, or R7' and R7 may form a ring with the adjacent nitrogen atom, and R8 represents a hydrocarbon group or a heterocyclic group), R5 represents a hydrocarbon group or a heterocyclic group (except for a quinolyl group), R5' represents a hydrogen atom, or a hydrocarbon group, or R5 and R5' may form a ring with the adjacent nitrogen atom, and R5" represents a hydrogen atom or a hydrocarbon group, which have vanilloid receptor agonist activity and are useful as a drug such as an analgesic and an agent for preventing and/or treating urinary frequency and/or urinary incontinence.
- -
-
-
- Rhodium-catalyzed addition of arylstannanes to carbon-heteroatom double bond
-
The addition of arylstannanes to the carbon-heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)2]BF4) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation with the arylstannane was probably the active catalytic species.
- Oi, Shuichi,Moro, Mitsutoshi,Fukuhara, Hiroe,Kawanishi, Takanori,Inoue, Yoshio
-
p. 4351 - 4361
(2007/10/03)
-
- N-methylpyrrolidine-zinc borohydride: As a new stable and efficient reducing agent in organic synthesis
-
N-Methylpyrrolidine-zinc borohydride is readily prepared and used for reduction of a variety of organic compounds such as aldehydes, ketones, acid chlorides, and esters. Reactions are performed in THF at room temperature or under reflux condition and the yields are good to excellent. Complete regio-selectivity are observed in reduction of α,β-unsaturated carbonyl compounds.
- Tajbakhsh,Lakouraj,Mohanazadeh,Ahmadi-Nejhad
-
p. 229 - 236
(2007/10/03)
-
- Generation of functionalized asymmetric benzynes with TMP-zincates. Effects of ligands on selectivity and reactivity of zincates
-
We have developed new methods for preparing functionalized benzynes through deprotonative zincation as a key reaction using R2Zn(TMP)Li, and we also describes dramatic ligand effects on the benzyne formation. Deprotonative zincation of various meta-substituted bromobenzenes with Me2Zn(TMP)Li proved effective for the one-pot generation of various 3-functionalized benzynes, particularly those electrophilic substituents such as ester, amide, and cyano. On the other hand, zincation with tBu2Zn(TMP)Li, followed by electrophilic trapping (with I2) proved a powerful tool for the preparation of 1,2,3-trisubstituted aromatic compounds.8 The resultant 1,2,3-trisubstituted benzenes are available as precursors for generation of 3-substituted benzynes by halogen-zinc exchange reactions with Me3ZnLi. These methods offer far greater generality than previous methods for the synthesis of functionalized asymmetric benzynes, and should be of value in new syntheses of various natural products and functional materials. In addition, these results underline the utility of spectator ligands on the central metal of ate complexes as a tunable functionality in the development of new ate complex-promoted reactions. Copyright
- Uchiyama, Masanobu,Miyoshi, Tomoko,Kajihara, Yumiko,Sakamoto, Takao,Otani, Yuko,Ohwada, Tomohiko,Kondo, Yoshinori
-
p. 8514 - 8515
(2007/10/03)
-
- Selective hydrogenation of benzophenones to benzhydrols. Asymmetric synthesis of unsymmetrical diarylmethanols
-
(Graph presented) trans-RuCl2[P(C6H4-4-CH3) 3]2(NH2CH2CH2NH 2) acts as a highly effective precatalyst for the hydrogenation of a variety of benzophenone derivatives to benzhydrols that proceeds smoothly at 8 atm and 23-35 °C in 2-propanol containing t-C4H9OK with a substrate/catalyst ratio of 2000-20000. Use of a BINAP/chiral diamine Ru complex effects asymmetric hydrogenation of various ortho-substituted benzophenones and benzoylferrocene to chiral diarylmethanols with consistently high ee.
- Ohkuma, Takeshi,Koizumi, Masatoshi,Ikehira, Hideyuki,Yokozawa, Tohru,Noyori, Ryoji
-
p. 659 - 661
(2007/10/03)
-
- 3'-Chloro-3α-(diphenylmethoxy)tropane but not 4'-chloro-3α- (diphenylmethoxy)tropane produces a cocaine-like behavioral profile
-
A series of 2'- and 3'-substituted and 3',3''-disubstituted 3α- (diphenylmethoxy)tropane analogs were designed and synthesized as novel probes for the dopamine transporter. All the analogs were evaluated for displacement of [3H]WIN 35,428 binding at the dopamine transporter and for inhibition of [3H]dopamine uptake in rat caudate putamen. Compounds were observed to monophasically displace [3H]WIN 35,428 binding to the dopamine transporter with affinities of 21.6-1836 nM (K(i)). Generally, meta- substituted compounds were more potent than benztropine and equipotent to or slightly less potent than their previously reported parasubstituted homologs in inhibiting [3H]WIN 35,428 binding. However, these same metasubstituted analogs were typically less potent than the 4'-substituted analogs in inhibiting [3H]dopamine uptake. Ortho-substituted analogs were generally less potent in both binding and inhibition of uptake at the dopamine transporter than either benztropine or other aryl-substituted homologs. The analogs were also tested for binding at norepinephrine and serotonin transporters as well as muscarinic m1 receptors. None of the compounds in the present study bound with high affinity to either the norepinephrine or serotonin transporters, but all bound to muscarinic m1 receptors with high affinity (K(i) = 0.41-2.52 nM). Interestingly, 3'-chloro-3α- (diphenylmethoxy)tropane (5c) produced effects like cocaine in animals trained to discriminate 10 mg/kg cocaine from saline, unlike its 4'-Cl homolog and all of the previously evaluated benztropine analogs. Further evaluation of compound 5c and the other benztropine analogs will undoubtedly prove useful in the elucidation of the role of the dopamine transporter in the reinforcing effects of cocaine and the ultimate identification of a cocaine-abuse treatment.
- Kline, Richard H.,Izenwasser, Sari,Katz, Jonathan L.,Joseph, David B.,Bowen, Wayne D.,Newman, Amy Hauck
-
p. 851 - 857
(2007/10/03)
-
- Benzylphosphonic acid inhibitors of human prostatic acid phosphatase
-
A series of α-substituted benzylphosphonic acids is described as inhibitors of human prostatic acid phosphatase, an enzyme has been used as a model to study aryl phosphatases. The most potent inhibitors in this series are 2-trifluoromethylbenzhydrylphosphonic acid (9 μM), and α-(2-phenylethyl)benzylphosphonic acid (14 μM). The structure-activity studies suggest that bulk tolerance beyond the phosphate binding area limits the steric or hydrophobic contribution to inhibitor potency achieved through α-carbon substitution.
- Schwender,Beers,Malloy,Cinicola,Wustrow,Demarest,Jordan
-
p. 311 - 314
(2007/10/03)
-
- Asymmetric Reduction of ortho-Substituted Benzophenones with B-Chlorodiisopinocampheylborane: A Convenient Synthesis of Enantiomerically Enriched Benzhydrols
-
A very efficient synthesis of chiral benzhydrols from ortho-substituted benzophenones is described which presumably utilizes a heteroatom-directed, intramolecular asymmetric reduction of ketones with B-chlorodiisopinocampheylborane.
- Shieh, Wen-Chung,Cantrell, William R.,Carlson, John A.
-
p. 3797 - 3800
(2007/10/02)
-
- Reaction of Halo(trimethylsilyl)benzenes with Electrophiles and Bases - Carbodesilylation and Elimination as Competitive Reactions
-
Eliminationto dehydrobenzenes takes place as competitive reaction in the base-catalyzed carbodesilylation of 1-halo-2-(trimethylsilyl)benzenes 1 with carbonyl compounds 2 in the presence of furans 3, 6.Elimination is preferred with increasing leaving tendency of the halides (I > Br >> Cl >>F) and with decreasing reactivity of the carbonyl compounds.Exclusive elimination to 1,2-didehydrobenzenes - which are trapped with furans - occurs in the reaction when no electrophiles are present. Key Words: Halo(trimethylsilyl)benzenes, carbodesilylation and elimination of / Carbodesilylation / Elimination
- Effenberger, Franz,Daub, Wolfgang
-
p. 2113 - 2118
(2007/10/02)
-
- Comparative Mechanistic Study of the Reaction of Benzophenone with n-BuMgBr and n-BuLi
-
Substituent effects on reactivity and product distribution (addition vs reduction) were determined for the reactions of benzophenones with n-BuMgBr and n-BuLi at 0 deg C.In case of the reaction with n-BuMgBr, meta and para-substituted benzophenones gave a reasonably linear Hammet plot, from which the ρ value of 1.45 was calculated, while ortho-substituted derivatives deviated downward from the correlation line.In contrast, the reaction with n-BuLi exhibit very small substituent effects on reactivity.The product distrubution is highly dependent on substituents in the n-BuMgBr reaction, whereas it is essentially independent of substituents in the n-BuLi reaction.Mechanistic differences between the reactions of these two reagents are discussed on the basis of these experimental results.
- Yamataka, Hiroshi,Miyano, Nobutaka,Hanafusa, Terukiyo
-
p. 2573 - 2575
(2007/10/02)
-
- ASSYMETRIC REDUCTIONS OF KETONES USING LITHIUM ALUMINIUM HYDRIDE MODIFIED WITH N,N-DIALKYL DERIVATIVES OF (R)-(-)-2-AMINOBUTAN-1-OL
-
LiAlH4 previuosly treated with 2 equivalents of (R)-(-)-2-(2-iso-indolinyl)butan-1-ol (a readily available reagent) reduced 2-chloro and 2,4-dimethyl benzophenones into the corresponding benzhydrols with 100percent enantiomeric excess.Other examples of ketone reductions are given.
- Brown, Eric,Penfornis, Annie,Bayma, Joaquim,Touet, Joeul
-
p. 339 - 342
(2007/10/02)
-
- Studies on Enantioselective Addition of Chiral Titanium Reagents to Aromatic Aldehydes
-
A series of substituted chiral benzhydrols were synthesized by reaction of aromatic aldehydes with the chiral intermediates formed from chiral titanates and arylmagnesium halides.The effect of substituents on the enantioselectivity of the reaction is studied.The reactions are carried out with two different chiral intermediates using two different procedures.
- Wang, Ji-Tao,Fan, Xiuju,Feng, Xiao,Qian, Yi-Min
-
p. 291 - 292
(2007/10/02)
-
- NITRIC ACID FACILE OXIDATION OF MONO- AND DIARYLCARBINOLS TO CARBONYL COMPOUNDS IN A BIPHASIC SYSTEM
-
A biphasic (nitromethane-water) process is provided for the oxidation of mono- and diarylcarbinols by aqueous nitric acid (20percent).The reported process represents a preparatively useful and convenient route to carbonyl compounds.
- Gasparrini, F.,Giovannoli, M.,Misiti, D.,Natile, G.,Palmieri, G.
-
-