- Sodium organoaluminate containing bidentate pyrrolyl ligand: Synthesis, structure, and catalytic activity for the Tishchenko reaction
-
An novel sodium organoaluminate containing bidentate pyrrolyl ligand [C4H3NH(2-CH2NHtBu)] was efficiently synthesized and characterized by X-ray crystallography. The molecular structure shows it is a monodimensional infinite chain structures with linear arrangements. Its basic repeat unit comprises the Al atom bonded to two deprotonated pyrrole rings and Na atom coordinated to of nitrogen atoms of –NtBu fragment, which undergoes further to coordinates a pyrrolyl ring of an adjacent molecule in a ?2-fasion. Furthermore, this sodium organoaluminate exhibited high catalytic activities for Tishchenko reaction.
- Liu, Yu,Guo, Zhiqiang,Wang, Yakong
-
-
- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
-
Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
-
p. 803 - 808
(2021/07/20)
-
- A rutheniumcis-dihydride with 2-phosphinophosphinine ligands catalyses the acceptorless dehydrogenation of benzyl alcohol
-
The first ruthenium dihydride complex featuring a phosphinine ligandcis-[Ru(H)2(2-PPh2-3-Me-6-SiMe3-PC5H2)2] was synthesised exclusively as thecis-isomer. When formedin situfrom the reaction ofcis-[Ru(Cl)2(2-PPh2-3-Me-6-SiMe3-PC5H2)2] with two equivalents of Na[BHEt3], as demonstrated by31P and1H NMR spectroscopy, the catalysed acceptorless dehydrogenation of benzyl alcohol was observed leading to benzyl benzoate in up to 70% yield.
- Andresen, John M.,Delve, Matthew P.,Luz, Christian,Mansell, Stephen M.,Newland, Robert J.,Trodden, Elizabeth C.
-
supporting information
p. 13407 - 13411
(2021/10/12)
-
- N-Heterocyclic Carbene Catalyzed Ester Synthesis from Organic Halides through Incorporation of Oxygen Atoms from Air
-
Oxygenation reactions with molecular oxygen (O2) as the oxygen source provides a green and straightforward strategy for the construction of O-containing compounds. Demonstrated here is a novel N-heterocyclic carbene (NHC) catalyzed oxidative transformation of simple and readily available organic halides into valuable esters through the incorporation of O-atoms from O2. Mechanistic studies prove that the deoxy Breslow intermediate generated in situ is oxidized to a Breslow intermediate for further transformation by this oxidative protocol. This method broadens the field of NHC catalysis and promotes oxygenation reactions with O2.
- Tan, Hui,Wang, Shen-An,Yan, Zixi,Liu, Jianzhong,Wei, Jialiang,Song, Song,Jiao, Ning
-
supporting information
p. 2140 - 2144
(2020/12/01)
-
- Thermally regulated molybdate-based ionic liquids toward molecular oxygen activation for one-pot oxidative cascade catalysis
-
One-pot oxidative cascade catalysis plays a central role in the synthesis of key pharmaceutical and industrial molecules. Although ionic liquids are one of the most promising solvents and reaction media, the breakthrough of their catalysis in aerobic oxidation is very challenging due to the difficulty in the direct activation of molecular oxygen. Herein, a family of novel thermally regulated molybdate-based ionic liquids (Mo-ILs) has been designed and developed for the first time toward molecular oxygen activation for highly efficient tandem oxidative catalysis. Three diverse one-pot oxidative cascade processes for the syntheses of various flavones, imines, and benzyl benzoates were achieved with good to excellent yields using the Mo-IL [Bmim]2[MoO4] as a catalyst under air conditions. The results of spectroscopic investigations and quantum-chemical calculations further demonstrated that a thermally regulated proton migration between the cation [Bmim] and anion [MoO4] was the key to forming N-heterocyclic carbene and thereby to effortlessly promoting the generation of O2- active species from molecular oxygen, which results in excellent catalytic performance in these three aerobic tandem oxidations. Our work extends the application area of ILs as the sole catalyst to one-pot aerobic oxidative cascade catalysis, which could have pronounced implications in future work.
- Song, Zhibin,Huang, Wei,Zhou, Yan,Tian, Zi-Qi,Li, Zhang-Min,Tao, Duan-Jian
-
supporting information
p. 103 - 109
(2020/01/21)
-
- Direct oxidative esterification of primary alcohols and oxidation of secondary alcohols over mesoporous spherical silica encapsulated MnO2 nanoparticles
-
In this work, a simple and efficient strategy for the fabrication of novel encapsulated MnO2 nanoparticles inside spherical mesoporous silica hollow-nanoparticles was described. They were synthesized by consecutively anchoring MnO2 nanoparticles on poly(styrene-co-methacrylic acid) particles, coating with a mesoporous silica shell, and subsequently removing the polymeric core by dissolving in acetone. The catalytic activity of the nanoparticles was examined in the aerobic oxidation of various primary and secondary alcohols, which showed good activity and selectivity for the transformation of primary alcohols to the corresponding esters through the oxidative esterification process and secondary alcohols to ketones in short reaction times under mild reaction conditions. In addition, the catalyst system was utilized for the oxidation of primary alcohols to aldehydes using tert-butyl hydroperoxide (TBHP) as an oxidant under mild conditions and produced an excellent product yield.
- Hosseinzadeh, Shahram Zare,Babazadeh, Mirzaagha,Shahverdizadeh, Gholam Hossein,Hosseinzadeh-Khanmiri, Rahim
-
p. 9491 - 9499
(2019/06/21)
-
- A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
-
An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.
- Manasa, Kesari Lakshmi,Tangella, Yellaiah,Krishna, Namballa Hari,Alvala, Mallika
-
p. 1864 - 1871
(2019/08/12)
-
- Synthesis, characterization and catalytic performances of benzimidazolin-2-iminato actinide (IV) complexes in the Tishchenko reactions for symmetrical and unsymmetrical esters
-
A new family of benzimdazolin-2-iminato actinide?(IV) complexes [(Bim7-MeDipp/MeN)An(N(SiMe3)2)3] (An = U (3), Th (4)) and [(Bim4-MeDipp/MeN)An(N(SiMe3)2)3] (An = U (5), Th (6)) were synthesized and their solid state structures were established by single-crystal X-ray diffraction analysis. The catalytic performances of complexes 3–6 towards the homo- and cross-coupling of aldehydes (Tishchenko reaction) were studied and the thorium complexes 4 and 6 displayed moderate to high activities for the production of the corresponding symmetric and unsymmetrical esters. Coupling of aldehyde and alcohols, known as the tandem proton-transfer esterification, and the intermolecular coupling reaction between aldehyde and trifluoromethylketones were also investigated by these thorium complexes, indicating a complementary method to obtain unsymmetrical esters selectively. Plausible mechanisms for these reactions are proposed based on stoichiometric studies.
- Liu, Heng,Khononov, Maxim,Fridman, Natalia,Tamm, Matthias,Eisen, Moris S.
-
p. 123 - 137
(2017/10/25)
-
- A animal pen halogen oxidation autoconnected joint into aromatic benzyl ester method (by machine translation)
-
The invention discloses an animal pen halogen oxidation autoconnected joint into aromatic benzyl ester method, organic solvent, animal pen halogen in the 1, 3 - double (2, 4, 6 - trimethyl-phenyl) imidazole and chloride under the action of alkali, one-step synthesis of benzoic acid benzyl ester; wherein the reaction form is: X chlorine, bromine or iodine, R is hydrogen, C1 - C4 alkyl, alkoxy, nitro, chlorine, bromine or fluorine. The invention mild reaction conditions, easy operation processing, the atom economy is high, the production cost is low. (by machine translation)
- -
-
Paragraph 0064; 0065; 0071
(2019/01/05)
-
- Thorium complexes possessing expanded ring N-heterocyclic iminato ligands: Synthesis and applications
-
Six and seven membered N-heterocyclic iminato ligands (L) are introduced allowing access a new class of Th(iv) complexes of the type Cp?2Th(L)(CH3). These complexes were studied in the Tishchenko reaction. Stoichiometric reactions together with kinetic and thermodynamic studies permit us to propose a plausible mechanism.
- Ghatak, Tapas,Drucker, Shani,Fridman, Natalia,Eisen, Moris S.
-
supporting information
p. 12005 - 12009
(2017/09/25)
-
- Aluminum complexes of β-hydroxy-imino ligands: Synthesis, structures and application in the Tishchenko reaction
-
Four aluminum alkoxide complexes containing β-hydroxy-imino ligands, [(2,6-Me2C6H3)NCPhCH2CPh2O]2AlMe (3a), [(2,6-iPr2C6H3)NCPhCH2CPh2O]2AlMe (3b), [(2,6-Me2C6H3)NCPhCH2C(C12H8)OAlMe2]2 (3c) and [(2,6-iPr2C6H3)NCPhCH2C(C12H8)OAlMe2]2 (3d) were synthesized in high yields, and their structural features were provided. The catalytic behavior of those four complexes about the Tishchenko reaction with a range of aromatic aldehydes as substrates were assessed, and it present a synthetically useful protocol to the solvent-free Tishchenko reaction under mild conditions.
- Guo, Zhiqiang,Wang, Song,Wei, Xuehong
-
p. 115 - 122
(2016/07/06)
-
- Formamides as Lewis Base Catalysts in SNReactions—Efficient Transformation of Alcohols into Chlorides, Amines, and Ethers
-
A simple formamide catalyst facilitates the efficient transformation of alcohols into alkyl chlorides with benzoyl chloride as the sole reagent. These nucleophilic substitutions proceed through iminium-activated alcohols as intermediates. The novel method, which can be even performed under solvent-free conditions, is distinguished by an excellent functional group tolerance, scalability (>100 g) and waste-balance (E-factor down to 2). Chiral substrates are converted with excellent levels of stereochemical inversion (99 %→≥95 % ee). In a practical one-pot procedure, the primary formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles. The value of the method was demonstrated in straightforward syntheses of the drugs rac-Clopidogrel and S-Fendiline.
- Huy, Peter H.,Motsch, Sebastian,Kappler, Sarah M.
-
supporting information
p. 10145 - 10149
(2016/08/16)
-
- Dicopper Complexes with Anthyridine-Based Ligands: Coordination and Catalytic Activity
-
Two new anthyridine-based ligands, 5-phenyl-2,8-bis(2-pyridinyl)-1,9,10-anthyridine (L3) and 5-phenyl-2,8-bis(6′-bipyridinyl)-1,9,10-anthyridine (L4), were designed for accommodation of dimetallic systems with the metal ions separated by 5 ?. Complexation of Cu(ClO4)2 with L3 and L4 provided the corresponding dicopper complexes [{Cu2(L3)(H2O)4(CH3CN)2}(ClO4)4] (3) and [{Cu2(L4)(μ-ClO4)2}(PF6)2] (4), respectively. Both complexes were characterized by spectroscopic methods, and the detail structural features were further confirmed by X-ray crystallography. Structural analyses of 3 and 4 reveal the Cu···Cu distances in the complexes being 4.9612(7) and 5.013 (2) ?, respectively. Both complexes are active in the catalytic oxidation of benzyl alcohols into the corresponding aldehydes. Furthermore, complex 4 appears to be a good catalyst for the oxidative coupling of primary alcohols into the corresponding esters with the use of hydrogen peroxide as the oxidant in an aqueous medium. The possible cooperative interactions between the metal ions during the catalysis are discussed.
- Huang, Da-Wei,Liu, Yi-Hung,Peng, Shie-Ming,Liu, Shiuh-Tzung
-
p. 151 - 158
(2016/02/05)
-
- Bulky guanidinate stabilized homoleptic magnesium, calcium and zinc complexes and their catalytic activity in the Tishchenko reaction
-
Bulky guanidinate stabilized homoleptic complexes of [LM(thf)nL] [L = {ArNC (NiPr2)NAr} (Ar = 2,6- Me2-C6H3)]; M = Mg, Ca, and Zn; n = 0-1) have been synthesized with three different synthetic routes. First, treatment of bis{bis(trimethylsilyl)amide}s of Mg, Ca, and Zn i.e. [M{(N(SiMe3)2}2] (M = Mg, Ca(thf)2, and Zn) with free guanidine ligand (LH) at 80 °C, elimination of NH(SiMe3)2 and formation of [LM(thf)nL] (M = Mg, Ca and Zn; n = 0-1) (3-5) complexes were occurred. Second, the reaction of two equivalents of potassium salt of LH with metal dihalides via salt metathesis led to the formation of homoleptic complexes. Third, the reaction between MR2 (M = Mg, Ca, Zn; R = alkyl or OTf) and LH at reflux temperature, formation of bis(guanidinate) magnesium, calcium, and zinc complexes have been observed. The solid state structures of LH(1), LK(2) and all three bis(guanidinate) magnesium, calcium and zinc complexes (3-5) were confirmed by X-ray structural analysis. Furthermore, dimerization of a range of aromatic, heteroaromatic and aliphatic aldehydes (Tishchenko reaction) has been demonstrated by using catalysts 3-5.
- Barman, Milan Kr,Baishya, Ashim,Nembenna, Sharanappa
-
-
- The promoted Tishchenko reaction and catalytic intermediate by 2-aminopyrrolyl dilithium compounds
-
The dimerization of aldehydes to the analogous carboxylic esters (Tischenko reaction) has been achieved in impressive yields using the dilithium compounds containing bidentate di-anionic pyrrolyl ligands as initiators. The initiated intermediate {[2-(tBuNCH)C4H3NLi][PhCH2OLi(TMEDA)]}2 was isolated and characterized by satisfactory C, H and N microanalysis, 1H, 13C{1H} and 7Li NMR spectra in pyridine-d5 at ambient temperature, and single crystal X-ray structural data. The processes involve a redox reaction of 2-aminopyrrolyl dilithium compound with aldehyde.
- Guo, Zhiqiang,Wei, Xuehong,Tong, Hongbo,Chao, Jianbin,Liu, Diansheng
-
supporting information
p. 73 - 76
(2015/03/14)
-
- Mixed Imidazolin-2-iminato-Cp? Thorium(IV) Complexes: Synthesis and Reactivity Toward Oxygen-Containing Substrates
-
The mixed pentamethylcyclopentadienyl thorium(IV) imidazolin-2-iminato complexes Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) were synthesized in quantitative yields via rapid protonolysis of Cp?2Th(Me)2 (1) with the respective neutral imidazolin-2-iminato ligand ImRNH. Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) display short Th-N bond lengths and large Th-N-C angles. The reactivity of complex 2 and 3 toward oxygen-containing substrates was studied, and the catalytic activity of 2 was compared to the dimethyl (bispentamethyl-cyclopentadienyl) thorium complex 1. Complex 2 was applied in the catalytic Tishchenko reaction with aromatic, heteroaromatic, and branched aliphatic aldehydes, displaying a higher catalytic activity than Cp?2Th(Me)2 and Cp?2Th(ImMesN)(Me). Furthermore, 2 was applied as a catalyst in the crossed Tishchenko reaction and in the oligomerization of bis(aldehydes), as well as in the ring-opening polymerization of ε-caprolactone. In all reactions, the activity of Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) was higher than that observed for Cp?2Th(Me)2 (1), which can be attributed to the increased electron density introduced by the coordination of the imidazolin-2-iminato ligand. (Chemical Equation Presented).
- Karmel, Isabell S. R.,Fridman, Natalia,Tamm, Matthias,Eisen, Moris S.
-
supporting information
p. 2933 - 2942
(2015/06/30)
-
- A simple procedure for the oxidation of alcohols using [bis(acetoxy)iodo]benzene and a catalytic amount of bromide ions in ethyl acetate
-
Abstract Primary and secondary benzylic alcohols and secondary aliphatic alcohols were oxidized to the corresponding aldehydes and ketones by using [bis(acetoxy)iodo]benzene (BAIB) and a catalytic amount of bromide ions, from tetrabutylammonium bromide or KBr, in ethyl acetate. The catalytic role of the bromide ions was also highlighted in the oxidation of primary aliphatic alcohols and secondary allylic alcohols carried out in the presence of 1 mol% TEMPO.
- Salvo, Anna Maria Pia,Campisciano, Vincenzo,Beejapur, Hazi Ahmad,Giacalone, Francesco,Gruttadauria, Michelangelo
-
p. 1179 - 1184
(2015/06/02)
-
- Mono(imidazolin-2-iminato) actinide complexes: Synthesis and application in the catalytic dimerization of aldehydes
-
The synthesis of the mono(imidazolin-2-iminato) actinide(IV) complexes [(ImRN)An(N{SiMe3)2}3] (3-8) was accomplished by the protonolysis reaction between the respective imidazolin-2-imine (ImRNH, R = tBu, Mes, Dipp) and the actinide metallacycles [{(Me3Si)N}2An{κ2C,N-CH2SiMe2N(SiMe3)}] (1, An = U; 2, M = Th). The thorium and uranium complexes were obtained in high yields, and their structures were established by single-crystal X-ray diffraction analysis. The mono(imidazolin-2-iminato) actinide complexes 3-8 display short An-N bonds together with large An-N-C angles, indicating strong electron donation from the imidazolin-2-iminato moiety to the metal, corroborating a substantial π-character to the An-N bond. The reactivity of complexes 3-8 toward benzaldehyde was studied in the catalytic dimerization of aldehydes (Tishchenko reaction), displaying low to moderate catalytic activities for the uranium complexes 3-5 and moderate to high catalytic activities for the thorium analogues 6-8, among which 8 exhibited the highest catalytic activity. In addition, actinide coordination compounds showed unprecedented reactivity toward cyclic and branched aliphatic aldehydes in the catalytic Tishchenko reaction mediated by the thorium complex [(ImDippN)Th{N(SiMe3)2}3] (8), exhibiting high activity even at room temperature. Moreover, complex 8 was successfully applied in the crossed Tishchenko reaction between an aromatic or polyaromatic and an aliphatic cyclic and branched aldehyde, yielding selectively the asymmetrically substituted ester in high yields (80-100%).
- Karmel, Isabell S. R.,Fridman, Natalia,Tamm, Matthias,Eisen, Moris S.
-
p. 17180 - 17192
(2015/02/02)
-
- Easy access to benzylic esters directly from alkyl benzenes under metal-free conditions
-
An efficient metal free protocol has been developed for the synthesis of benzylic esters via a cross dehydrogenative coupling (CDC) involving alkylbenzene(s) as a self- or as a cross-coupling partner(s) via the intermediacy of Ar-COOH and the benzylic carbocation obtained from the other half of the alkylbenzene; both symmetrical as well as unsymmetrical esters can be prepared using Bu4NI and TBHP. The Royal Society of Chemistry.
- Majji, Ganesh,Guin, Srimanta,Gogoi, Anupal,Rout, Saroj Kumar,Patel, Bhisma K.
-
supporting information
p. 3031 - 3033
(2013/05/09)
-
- Pt, Pd and Au nanoparticles supported on a DNA-MMT hybrid: Efficient catalysts for highly selective oxidation of primary alcohols to aldehydes, acids and esters
-
Novel DNA-MMT hybrid supported metal nanoparticle catalysts, such as Pt/DNA-MMT, Pd/DNA-MMT, Au/DNA-MMT, were prepared for application in highly selective aerobic oxidation of primary alcohols to aldehydes, acids and esters, respectively. Taking advantage of the water-soluble reversibility of these catalysts, all the transformations could be performed smoothly in water and reuse of the catalysts has also been accomplished by a very simple phase separation process.
- Tang, Lin,Guo, Xuefeng,Li, Yunfeng,Zhang, Shuai,Zha, Zhenggen,Wang, Zhiyong
-
supporting information
p. 5213 - 5215
(2013/06/27)
-
- Preparation of esters and amides from carboxylic acids and N-formylation of amines promoted by 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC)
-
A new method is described for the preparation of esters and amides promoted by TAPC from carboxylic acids using a solvent-free grinding technique. The solvent-free N-formylation of amines is also reported.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Targhan, Homa,Sheikh Arabi, Mehdi
-
supporting information
p. 5064 - 5068
(2013/09/02)
-
- Photolytic decomposition of dibenzylic sulfites
-
The photolytic decay of a library of para-substituted dibenzylic sulfites has been evaluated by UV radiation in a Srinivasan-Griffin-Rayonet photochemical reactor in various deuterated solvents. The decay for each dibenzylic sulfite was examined with respect to Swain and Lupton's field constant, F. The rate of photolytic decay varies depending on the identity of the benzyl substituents. Furthermore, it has been observed that the solvent affects both the rate of sulfite photolytic decay as well as final product distribution.
- Grenga, Paolo N.,Stoutenburg, Eric G.,Priefer, Ronny
-
p. 4933 - 4937
(2012/11/13)
-
- Copper catalyzed oxidative esterification of aldehydes with alkylbenzenes via cross dehydrogenative coupling
-
Copper(II) as the catalyst in a cross dehydrogenative coupling (CDC) reaction has been demonstrated for the synthesis of benzylic esters using aldehydes and alkylbenzenes as coupling partners.
- Rout, Saroj Kumar,Guin, Srimanta,Ghara, Krishna Kanta,Banerjee, Arghya,Patel, Bhisma K.
-
supporting information; experimental part
p. 3982 - 3985
(2012/09/22)
-
- An efficient synthesis of α-hydroxy phosphonates and 2-nitroalkanols using Ba(OH)2 as catalyst
-
The α-hydroxy phosphonates have been synthesized using simple, inexpensive, and commonly available Ba(OH)2·8H2O at room temperature and quantitative yields were obtained in just 15 min for most of the reactions. On applying the same reaction condition to aqueous mediated Henry reaction, 2-nitroalkanols were obtained in good to excellent yield within 15 min.
- Pandi, Muthupandi,Chanani, Prem Kumar,Govindasamy, Sekar
-
p. 119 - 123
(2012/10/29)
-
- Organoactinides promote the dimerization of aldehydes: Scope, kinetics, thermodynamics, and calculation studies
-
Surprising catalytic activities have been found for the actinide complexes Cp*2ThMe2 (1), Th(NEtMe)4 (2), and Me2SiCp″2Th(C4H9) 2(3) toward oxygenated substrates. During the catalytic dimerization of benzaldehydes to their corresponding esters, complexes 1 and 2 gave 65 and 85% yield in 48 h, respectively, while the geometry-constrained complex 3 gave 96% yield in 24 h. Exploring the effect of substituents on benzaldehyde, it has been found that, in general, electron-withdrawing groups facilitate the reaction. Kinetic study with complexes 1 and 3 reveals that the rate of the reaction is first order in catalyst and substrate, which suggests the rate equation "rate = k[catalyst]1[aldehyde]1". The activation energy of the reaction was found to be 7.16 ± 0.40 and 3.47 ± 0.40 kcal/mol for complexes 1 and 3 respectively, which clearly indicates the advantage of the geometry-constrained complex. Astonishing are the reactivity of the organoactinide complexes with oxygen-containing substrates, and especially the reactivity of complex 3, toward the dimerization of substrates like p-methoxybenzaldehyde, m/p-nitrobenzaldehyde, and furanaldehyde and the reactivity toward the polymerization of terephthalaldehyde. Density functional theory mechanistic study reveals that the catalytic cycle proceeds via an initially four-centered transition state (+6 kcal/mol), followed by the rate-determining six-centered transition state (+13.5 kcal/mol), to yield thermodynamically stable products.
- Sharma, Manab,Andrea, Tamer,Brookes, Nigel J.,Yates, Brian F.,Eisen, Moris S.
-
experimental part
p. 1341 - 1356
(2011/04/16)
-
- N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides under aerobic conditions
-
An efficient N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonate is reported. It was worth noting that (1) the configuration of alkyl halides or alkyl 4-methylbenzenesulfonates was inverted completely, and (2) the presence of oxygen was crucial for this transformation. The reaction proceeded smoothly under mild conditions and various esters were afforded in moderate to good yields. In addition, we have developed an efficient tandem oxidation/ esterification reaction of alcohols. This methodology provides a rare example of a reaction of the Breslow intermediate to sp3-carbon centered electrophiles. An efficient oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonates catalyzed by N-heterocyclic carbenes is reported. Oxygenwas crucial for the reaction, and the configuration of alkyl 4-methylbenzenesulfonate was completely inverted. Copyright
- Xin, Yang-Chun,Shi, Shi-Hui,Xie, Dong-Dong,Hui, Xin-Ping,Xu, Peng-Fei
-
supporting information; experimental part
p. 6527 - 6531
(2011/12/22)
-
- Tunable bromomagnesium thiolate tishchenko reaction catalysts: Intermolecular aldehyde-trifluoromethylketone coupling
-
(Figure Presented) Applied knowledge: A new thiolate-catalyzed Tishchenko reaction inspired by biochemical processes features exceptionally good control over the catalyst's steric/electronic properties. The isolation of reaction intermediates provided valua-ble insights into the reaction mechanism, which in turn has allowed the development of the first cross-Tishchenko coupling reactions between aldehydes and activated ketones (see example).
- Cronin, Linda,Manoni, Francesco,O'Connor, Cornelius J.,Connon, Stephen J.
-
supporting information; experimental part
p. 3045 - 3048
(2010/07/05)
-
- Organocatalytic mitsunobu reactions with 3,5-dinitrobenzoic acid
-
A second generation procedure for organocatalytic Mitsunobu reactions using 3,5-dinitrobenzoic acid as the pro-nucleophile has been developed. The increased acidity of this acid compared to 4-nitrobenzoic acid, which was used in the original procedure, allowed for higher isolated yields of the desired products and eliminated formation of undesired acetate byproducts. Georg Thieme Verlag Stuttgart - New York.
- But, Tracy Yuen Sze,Lu, Jinni,Toy, Patrick H.
-
supporting information; experimental part
p. 1115 - 1117
(2010/06/19)
-
- Mild amidation of aldehydes with amines mediated by lanthanide catalysts
-
(Chemical Equation Presented) Catalytic amidation of aldehydes with amines is efficiently mediated by homoleptic lanthanide amido complexes, Ln[N(SiMe 3)2]3 (Ln = La, Sm, and Y). Amidation reactivity follows the trend: La > Sm ≈ Y. These reactions proceed in high yield without added oxidants, bases, and/or heat or light, which are usually required in other catalytic amidation processes. The reaction is demonstrated with a variety of amines, with yields as high as 98% based on amine.
- Seo, SungYong,Marks, Tobin J.
-
p. 317 - 319
(2008/09/19)
-
- Triphenylphosphine oxide supported on non-cross-linked maleimide-styrene copolymer: application as a novel Hendrickson reagent
-
A new triphenylphosphine oxide reagent linked to a linear maleimide-styrene copolymer is synthesized. This phosphine-bound copolymer is converted to copolymer-supported triphenylphosphine ditriflate as a novel Hendrickson reagent by treatment with triflic anhydride. This reacts rapidly in various dehydration reactions such as anhydride, ester and amide formation. This linear and soluble support is also easily recovered and recycled several times without loss of efficiency.
- Mahdavi, Hossein,Amani, Javad
-
p. 2204 - 2207
(2008/09/18)
-
- Direct oxidative conversion of aldehydes and alcohols to 2-imidazolines and 2-oxazolines using molecular iodine
-
Aldehydes were converted to the corresponding 2-imidazolines and 2-oxazolines in good yields by the reaction with ethylenediamine and aminoethanol, respectively, using molecular iodine and potassium carbonate. Moreover, primary alcohols were directly converted to the corresponding 2-imidazolines and 2-oxazolines via aldehydes in one-pot manner with ethylenediamine and aminoethanol, respectively, using molecular iodine and potassium carbonate.
- Ishihara, Midori,Togo, Hideo
-
p. 1474 - 1480
(2007/10/03)
-
- Oxidation of benzylic alcohols with I2/K2CO 3/tert-butanol: Formation of aldehydes or dimeric esters
-
Oxidation of a series of aromatic and heteroaromatic benzylic alcohols with molecular iodine in tert-butanol in the presence of potassium carbonate has been studied. Oxidation of most benzylic alcohols affords the corresponding aldehydes in reasonable yields. The reaction has been shown to be compatible with amino, formyl, methylthio groups and thiophene ring in the molecule. Oxidation of the electron-poor benzylic alcohols such as nitrobenzyl alcohols and (benzimidazol-2-yl)methanol results in the formation of the corresponding dimeric esters.
- Tumkevicius,Navickas,Dailide
-
p. 1377 - 1383
(2007/10/03)
-
- Tishchenko reaction using an iridium-ligand bifunctional catalyst
-
Tishchenko reaction of aldehydes in the presence of an amino alcohol-based Ir bifunctional catalyst was developed. The reaction proceeds with 1 mol% of the catalyst and 20-30 mol% of K2CO3 in acetonitrile at room temperature to give the corresponding dimeric esters in good yield. Georg Thieme Verlag Stuttgart.
- Suzuki, Takeyuki,Yamada, Taichiro,Matsuo, Tomohito,Watanabe, Kazuhiro,Katoh, Tadashi
-
p. 1450 - 1452
(2007/10/03)
-
- Iridium-catalyzed oxidative dimerization of primary alcohols to esters using 2-butanone as an oxidant
-
Oxidative dimerization of primary alcohols with 2-butanone in the presence of an amino alcohol-based Ir bifunctional catalyst was accomplished for the first time. The reaction proceeds with 1-2 mol% of the catalyst and 0.3 mol equivalents of K2CO3 in 2-butanone at room temperature to give the corresponding dimeric esters in 30-93% yield. Georg Thieme Verlag Stuttgart.
- Suzuki, Takeyuki,Matsuo, Tomohito,Watanabe, Kazuhiro,Katoh, Tadashi
-
p. 1453 - 1455
(2007/10/03)
-
- Novel polymer-supported coupling/dehydrating reagents for use in organic synthesis
-
Two novel dehydrating reagents 3 and 4, based on a phosphonium anhydride and an oxyphosphonium triflate respectively, were prepared by reaction of the corresponding polymer-supported phosphine oxides with triflic anhydride. Reagent 3, based on the novel phosphorus heterocycle 1,1,3,3-tetraphenyl-2-oxa-1,3- diphospholanium bis(trifluoromethanesulfonate), was found to be a useful reagent for ester and amide formation. A wide range ofcoupling/dehydration-type reactions, such as ester, amide, anhydride, peptide, ether and nitrile formation, were performed in high yield using the more readily prepared polymer-supported triphenylphosphine ditrinate 4, which was easily recovered and re-used several times without loss of efficiency. With primary alcohols, both reagents 3 and 4 provide an alternative to the Mitsunobu reaction, where the use of azodicarboxylates and chromatography to remove the phosphine oxide by-product can be avoided. The use of 4-dimethylaminopyridine allowed the esterification of secondary alcohols with 4 to proceed in high yield but with retention of configuration.
- Fairfull-Smith, Kathryn E.,Jenkins, Ian D.,Longhlin, Wendy A.
-
p. 1979 - 1986
(2007/10/03)
-
- Polymer-supported triphenylphosphine ditriflate: A novel dehydrating reagent
-
A new type of polymeric dehydrating reagent, readily prepared by the treatment of polymer-supported triphenylphosphine oxide with triflic anhydride, was found to be effective in a variety of dehydration reactions such as ester and amide formation; the polymer-supported triphenylphosphine oxide was easily recovered and reused several times without the loss of activity.
- Elson, Kathryn E.,Jenkins, Ian D.,Loughlin, Wendy A.
-
p. 2491 - 2493
(2007/10/03)
-
- Cyclic analogues of the Hendrickson 'POP' reagent
-
The Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 'POP' 1, is a powerful dehydrating agent. Five-, six-, and seven-membered cyclic analogues of the 'POP' reagent 2-4 have been prepared and their use for ester and amide synthesis investigated. A kinetic comparison of the cyclic analogues 2-4 revealed that a considerable increase in the rate of esterification could be achieved when the five-membered ring analogue 2 was used, presumably due to the ease of formation of the putative phosphorane intermediate. The rate of ester formation from a primary alcohol using the Hendrickson reagent 1 was shown to be significantly faster when non-polar solvents were employed.
- Elson, Kathryn E.,Jenkins, Ian D.,Loughlin, Wendy A.
-
p. 371 - 376
(2007/10/03)
-
- The Hendrickson reagent and the Mitsunobu reaction: A mechanistic study
-
The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 1. Strangely, while the reagent 1 can be used in place of the Mitsunobu reagents (triphenylphosphine and a dialkylazodicarboxylate) for the esterification of primary alcohols, secondary alcohols such as menthol undergo elimination. Evidence is presented to show that this unexpected result is due to the presence of trialkylammonium triflate salts. Such salts lead to a dramatic decrease in the rate of esterification relative to competing elimination. The Mitsunobu esterification of menthol with p-nitrobenzoic acid was re-examined and the occurrence of elimination reported for the first time. The presence of traces of tetrabutylammonium triflate led to a dramatic reduction in the yield of inverted ester and a corresponding increase in the yield of anti elimination product 2-menthene. The mechanism of the Mitsunobu reaction is discussed in the light of the dramatic salt effect on both the rate and outcome of the reaction and the possible involvement of ion pair clustering. In contrast, use of the reagent 1 resulted in syn elimination to give a 1:2 mixture of 2- and 3-menthenes. Finally, 1 and sodium azide can be used to convert a primary alcohol into an azide in high yield. There was no reaction under Mitsunobu conditions.
- Elson, Kathryn E.,Jenkins, Ian D.,Loughlin, Wendy A.
-
p. 2958 - 2965
(2007/10/03)
-
- Synthesis of esters from acyl chlorides and halide under solid-liquid phase transfer catalysis
-
A new and general method for the synthesis of esters is reported. Acyl chloride reacts with halide in the presence of hydrogen carbonate and under solid-liquid phase transfer condition to afford the esters in good to excellent isolated yields. The effects of catalyst, sodium and solvents to the reactions have been investigated. The reaction mechanism is briefly discussed.
- Hu,Pa,Cui,Wang
-
p. 2763 - 2767
(2007/10/02)
-
- Homogeneous Metal-Catalyzed Sequential Rosenmund-Tishchenko Reactions
-
Esters can be isolated in good yields by the reaction of acid chlorides with hydrogen in the presence of 2,4,6-collidine and catalytic quantities of either (Ph3P)3Ru(H)Cl or (Ph3P)RuCl2 in toluene.Acrylruthenium hydrides are possible reaction intermediates.
- Grushin, Vladimir V.,Alper, Howard
-
p. 5159 - 5161
(2007/10/02)
-
- SULFONES FROM MONO- AND DITHIOACETALS AS SULFUR CHEMIST'S TOOL
-
Mainly applied syntheses of sulfones of O,S- and of S,S-acetals are briefly summarized; special types of these compounds represent the corresponding ketene acetals.Characteristic reactions all of these classes of compounds - including α sulfonyl carbanions as nucleophiles, α-substituted vinyl sulfones as Michael-acceptors or as cycloaddition partners, especially with regard to their synthon properties - are discussed.
- Schank, Kurt
-
p. 207 - 221
(2007/10/02)
-
- Trimethylamine-Borane a Useful Reagent in the One-Pot Preparation of Carboxylic Esters from Carboxylic Acids
-
The carboxylic esters 2a-h (R1CO2CH2R1) and 4a-d (R1CO2CH2R2) are synthesized from alkyl or aryl carboxylic acids, a one-pot reaction involving in situ reduction followed by esterification, both steps are mediated by trimethylamine-borane.
- Trapani, Giuseppe,Reho, Antonia,Latrofa, Andrea,Liso, Gaetano
-
p. 853 - 854
(2007/10/02)
-
- CONDENSATION OF SOME AROMATIC ALDEHYDES WITH DIMETHYL SULFONE
-
Condensation of some aromatic aldehydes with dimethyl sulfone using sodium amide has been studied.Majority of the aldehydes afforded cis-2,6-diaryl-1,4-oxathian-4,4-dioxides as the exclusive product. 4-Methoxybenzaldehyde, in addition, provided the bis α,
- Selvaraj, S.,Dhanabalan, A.,Perumal, S.,Arumugam, N.
-
p. 217 - 220
(2007/10/02)
-
- Lithium Tungsten Dioxide Promoted Claisen-Tishchenko Condensation of Aromatic and Aliphatic Aldehydes
-
Lithium tungsten dioxide, LiWO2, has been shown to be a useful catalyst for effecting the Claisen-Tishchenko condensation of aldehydes under heterogeneous conditions.
- Villacorta, Gilberto M.,Filippo, Joseph San
-
p. 1151 - 1154
(2007/10/02)
-