cas 6789-88-4, Hexyl benzoate | Articles data

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Electrochemical esterification via oxidative coupling of aldehydes and alcohols
An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
supporting information

(2021/03/26)

LiHMDS: Facile, highly efficient and metal-free transesterification under solvent-free condition
Transesterification is one of the important organic reactions employed in numerous industrial as well as laboratory applications for the synthesis of various esters. Herein, we report a rapid, highly efficient, and transition metal-free transesterification reaction in the presence of LiHMDS under solvent-free conditions. The transesterification reaction was carried out with three different benzoate esters and a wide range of primary and secondary alcohols (from C3-C18) in good to excellent yields (45 examples). By considering the commercial role of esters, this method will be promising for the facile synthesis of esters in industry-relevant applications.
Gore, Kiran R.,Mittapelli, Lavanya L.
(2020/10/27)

NaOTs-promoted transition metal-free C-N bond cleavage to form C-X (X = N, O, S) bonds
Multifunctional transformation of amide C-N bond cleavage is reported. The protocol applies to benzamide, thioamide, alcohols, and mercaptan under similar reaction conditions catalyzed by NaOTs. It is noteworthy that NaOTs can not only be recycled and reused for up to three cycles without significant loss in catalytic activity, but also catalyze gram-grade reactions. This study provides a novel solution with mild conditions and a simple procedure for transformation of multiple amides.
Chen, Wei,Liu, Sicheng,Liu, Tingting,Majeed, Irfan,Ye, Xiaojing,Zeng, Zhuo,Zhang, Yuqi,Zhu, Yulin
p. 8566 - 8571
(2021/10/20)

Zr-MOF-808 as Catalyst for Amide Esterification
In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.
Villoria-del-álamo, Beatriz,Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
supporting information
p. 4588 - 4598
(2020/12/25)

Practical Chemoselective Acylation: Organocatalytic Chemodivergent Esterification and Amidation of Amino Alcohols with N-Carbonylimidazoles
Chemoselective transformations are a cornerstone of efficient organic synthesis; however, achieving this goal for even simple transformations, such as acylation reactions, is often a challenge. We report that N-carbonylimidazoles enable catalytic chemodivergent aniline or alcohol acylation in the presence of pyridinium ions or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), respectively. Both acylation reactions display high and broad chemoselectivity for the target group. Unprecedented levels of chemoselectivity were observed in the DBU-catalyzed esterification: A single esterification product was obtained from a molecule containing primary aniline, alcohol, phenol, secondary amide, and N?H indole groups. These acylation reactions are highly practical as they involve only readily available, inexpensive, and relatively safe reagents; can be performed on a multigram scale; and can be used on carboxylic acids directly by in situ formation of the acylimidazole electrophile.
Brown, Hailee,Heller, Stephen T.,Light, Christina,Medlin, Abigail,Nelson, Hope,Richard, William
supporting information
p. 22818 - 22825
(2021/09/13)

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)

A Versatile Approach to Dynamic Amide Bond Formation with Imine Nucleophiles
Dynamic covalent chemistry has rapidly become an important approach to access supramolecular structures. While the products generated in these reactions are held together by covalent bonds, the reversible nature of the transformations can limit the utility of many these systems in creating robust materials. We describe herein a method to form stable and commonly employed amide bonds by exploiting the reversible coupling of imines and acyl chlorides. The reaction employs easily accessible reagents, is dynamic under ambient conditions, without catalysts, and can be trapped with simple hydrolysis. This offers an approach to create broad families of amide products under thermodynamic control, including the selective formation of amide macrocycles or polymers.
Arndtsen, Bruce A.,Erguven, Huseyin,Keyzer, Evan N.
supporting information

(2020/05/05)

The synergistic role of the support surface and Au-Cu alloys in a plasmonic Au-Cu?LDH photocatalyst for the oxidative esterification of benzyl alcohol with methanol
Layered double hydroxide-supported Au-Cu alloy nanoparticles (NPs) were found to be highly efficient catalysts for the oxidative esterification of benzyl alcohol with methanol in the presence of molecular oxygen under visible-light irradiation to prepare methyl benzoate. Here, we report that alloying small amounts of copper into gold nanoparticles can increase the ability to activate oxygen molecules to O2- radicals and display greater charge heterogeneity to promote the cleavage of the C-H bond of benzyl alcohol molecules by reinforcing the coordination of the intermediate with unsaturated metal active sites due to the LSPR effect of alloy NPs, which is the rate-limiting step of the reaction. Besides the Au-Cu alloy NPs, the support also played a pivotal role in the catalytic process. The support with the presence of acid-base pairs, in which the basic sites served as the reactant molecule adsorption sites to provoke the intermediate formation and the acidic sites promoted the recovery of the support surface, showed better performances by affecting the overall reaction rate completely. Moreover, applying this photocatalyst in the cross-esterification of aromatic alcohols and aliphatic alcohols displayed excellent yields.
Wang, Xiaoyu,Wang, Ruiyi,Wang, Jie,Fan, Chaoyang,Zheng, Zhanfeng
p. 1655 - 1664
(2020/01/31)

Hydrogenation of alkenes via cooperative hydrogen atom transfer
Radical hydrogenation via hydrogen atom transfer (HAT) to alkenes is an increasingly important transformation for the formation of thermodynamic alkane isomers. Current single-catalyst methods require stoichiometric oxidant in addition to hydride (H-) source to function. Here we report a new approach to radical hydrogenation: cooperative hydrogen atom transfer (cHAT), where each hydrogen atom donated to the alkene arrives from a different catalyst. Further, these hydrogen atom (H?) equivalents are generated from complementary hydrogen atom precursors, with each alkane requiring one hydride (H-) and one proton (H+) equivalent and no added oxidants. Preliminary mechanistic study supports this reaction manifold and shows the intersection of metal-catalyzed HAT and thiol radical trapping HAT catalytic cycles to be essential for effective catalysis. Together, this unique catalyst system allows us to reduce a variety of unactivated alkene substrates to their respective alkanes in high yields and diastereoselectivities and introduces a new approach to radical hydrogenation.
Kattamuri, Padmanabha V.,West, Julian G.
supporting information
p. 19316 - 19326
(2020/11/13)

Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
supporting information
p. 8143 - 8146
(2020/09/09)

IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
Talukdar, Ranadeep
supporting information
p. 5303 - 5308
(2020/04/17)

MnO2?Fe3O4 Magnetic Nanoparticles as Efficient and Recyclable Heterogeneous Catalyst for Benzylic sp3 C?H Oxidation
Herein, we report a highly chemoselective and efficient heterogeneous MnO2?Fe3O4 MNP catalyst for the oxidation of benzylic sp3 C?H group of ethers using TBHP as a green oxidant to afford ester derivatives in high yield under batch/continuous flow module. This catalyst was also effective for the benzylic sp3 C?H group of methylene derivatives to furnish the ketone in high yield which can be easily integrated into continuous flow condition for scale up. The catalyst is fully characterized by spectroscopic techniques and it was found that 0.424 % MnO2?Fe3O4 catalyzes the reaction; the magnetic nanoparticles of this catalyst could be easily recovered from the reaction mixture. The recovered catalyst was recycled for twelve cycles without any loss of the catalytic activity. The advantages of MnO2?Fe3O4 MNP are its catalytic activity, easy preparation, recovery, and recyclability, gram scale synthesis with a TOF of up to 14.93 h?1 and low metal leaching during the reaction.
Pandey, Akanksha M.,Agalave, Sandip G.,Vinod, Chathakudath P.,Gnanaprakasam, Boopathy
supporting information
p. 3414 - 3423
(2019/10/19)

Epoxide as precatalyst for metal-free catalytic transesterification
Transesterification of methyl esters was accelerated by an in situ-generated metal-free catalyst comprising a quaternary alkylammonium salt and an epoxide. The combination of a quaternary alkylammonium acetate and glycidol is optimal, and various esters were synthesized from methyl esters with alcohols in good to excellent yield. Analysis of the catalyst solution revealed that basic species are generated by the ring-opening reaction of epoxide.
Tanaka, Shinji,Nakashima, Takuya,Satou,Oono, Hiromi,Kon, Yoshihiro,Tamura, Masanori,Sato, Kazuhiko
p. 2009 - 2013
(2019/07/03)

Dehydrogenative cross-coupling of primary alcohols to form cross-esters catalyzed by a manganese pincer complex
Base-metal-catalyzed dehydrogenative cross-coupling of primary alcohols to form cross-esters as major products, liberating hydrogen gas, is reported. The reaction is catalyzed by a pincer complex of earth-abundant manganese in the presence of catalytic base, without any hydrogen acceptor or oxidant. Mechanistic insight indicates that a dearomatized complex is the actual catalyst, and indeed this independently prepared dearomatized complex catalyzes the reaction under neutral conditions.
Das, Uttam Kumar,Ben-David, Yehoshoa,Leitus, Gregory,Diskin-Posner, Yael,Milstein, David
p. 479 - 484
(2019/01/11)

Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
The presence of different aldehydes is found to have a significant influence on the catalytic performance when using PN(H)P type ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted the observed high chemoselectivity.
Jiang, Xiaolin,Zhang, Jiahui,Zhao, Dongmei,Li, Yuehui
p. 2797 - 2800
(2019/03/27)

Cesium Carbonate Catalyzed Esterification of N-Benzyl- N-Boc-amides under Ambient Conditions
We report a general activated amide to ester transformation catalyzed by Cs2CO3. Using this approach, esterification proceeds under relatively mild conditions and without the need for a transition metal catalyst. This method exhibits broad substrate scope and represents a practical alternative to existing esterification strategies. The synthetic utility of this protocol is demonstrated via the facile synthesis of crown ether derivatives and the late-stage modification of a representative natural product and several sugars in reasonable yields.
Ye, Danfeng,Liu, Zhiyuan,Chen, Hao,Sessler, Jonathan L.,Lei, Chuanhu
supporting information
p. 6888 - 6892
(2019/09/07)

Preparation method for synthesizing ester compound by using N-Boc amide as raw material
The invention relates to a preparation method for synthesizing an ester compound by using N-Boc amide as a raw material. According to the method, an inorganic base is used as a catalyst; the N-Boc amide is subjected to an intermolecular nucleophilic substitution reaction with various alcohol compounds; and various ester compounds can be efficiently obtained. The method has the advantages of beingmild in reaction condition, simple and convenient to operate, high in yield and favorable in functional-group compatibility.
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Paragraph 0015; 0016

(2019/03/28)

Esterification of Tertiary Amides by Alcohols Through C?N Bond Cleavage over CeO2
CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT-IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT-IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C?N bond cleavage reaction.
Toyao, Takashi,Nurnobi Rashed, Md.,Morita, Yoshitsugu,Kamachi, Takashi,Hakim Siddiki,Ali, Md. A.,Touchy,Kon, Kenichi,Maeno, Zen,Yoshizawa, Kazunari,Shimizu, Ken-ichi
p. 449 - 456
(2018/09/11)

Nickel-Catalyzed Amide Bond Formation from Methyl Esters
Despite being one of the most important and frequently run chemical reactions, the synthesis of amide bonds is accomplished primarily by wasteful methods that proceed by stoichiometric activation of one of the starting materials. We report a nickel-catalyzed procedure that can enable diverse amides to be synthesized from abundant methyl ester starting materials, producing only volatile alcohol as a stoichiometric waste product. In contrast to acid- and base-mediated amidations, the reaction is proposed to proceed by a neutral cross coupling-type mechanism, opening up new opportunities for direct, efficient, chemoselective synthesis.
Ben Halima, Taoufik,Masson-Makdissi, Jeanne,Newman, Stephen G.
p. 12925 - 12929
(2018/09/14)

Cross-Dehydrogenating Coupling of Aldehydes with Amines/R-OTBS Ethers by Visible-Light Photoredox Catalysis: Synthesis of Amides, Esters, and Ureas
A straightforward synthesis of amides, ureas, and esters is reported by visible-light cross-dehydrogenating coupling (CDC) of aldehydes (or amine carbaldehydes) and amines/R-OTBS ethers by photoredox catalysis. The reaction is found to be general and high yielding. A plausible mechanistic pathway has been proposed for these transformations and is supported by appropriate controlled experiments.
Pandey, Ganesh,Koley, Suvajit,Talukdar, Ranadeep,Sahani, Pramod Kumar
supporting information
p. 5861 - 5865
(2018/09/21)

Fluoride-Catalyzed Esterification of Amides
In recent years, it has been demonstrated that amide carbon–nitrogen bonds can be activated and selectively cleaved using transition metal catalysts. However, these methodologies have been restricted to specific amides; a one-to-one relationship exists between the catalytic system and the amides and also uses large amounts of transition-metal catalysts and ligands. Hence, we now report a general strategy for esterification of common amides using fluoride as a catalyst. This method shows high functional group tolerance, and notably it requires only a slight excess of the alcohol nucleophile, which is a rare case in transition-metal-free amide transformations. Moreover, this approach may provide a new understanding for further studies on esterification of amides and is expected to stimulate the development of alternative methods for direct functionalization of amides.
Wu, Hongxiang,Guo, Weijie,Daniel, Stelck,Li, Yue,Liu, Chao,Zeng, Zhuo
p. 3444 - 3447
(2018/02/21)

Quaternary Alkyl Ammonium Salt-Catalyzed Transformation of Glycidol to Glycidyl Esters by Transesterification of Methyl Esters
Catalytic transformation of glycidol while maintaining its epoxide moiety intact is challenging because the terminal epoxide that interacts with the hydroxyl group via a hydrogen bond is labile for the ring-opening reaction. We found that a quaternary alkyl ammonium salt catalyzes the selective transformation of glycidol to glycidyl esters by transesterification of methyl esters. The developed method can be applied to the synthesis of multiglycidyl esters, which are valuable epoxy resin monomers. Mechanistic studies revealed the formation of a binding complex of glycidol and quaternary alkyl ammonium salt in a nonpolar solvent and the generation of the alkoxide anion as a catalyst through the ring-opening reaction of the epoxide. Computational studies of the reaction mechanism indicated that the alkoxide anion derived from glycidol tends to abstract the proton of another glycidol rather than work as a nucleophile, initiating the catalytic transesterification. Payne rearrangement of the deprotonated glycidol, which produces a destabilized base that promotes nonselective reactions, is energetically unfavorable due to the double hydrogen bond between the anion and diol. The minimal interaction between the quaternary alkyl ammonium cation and the epoxide moiety inhibited the random ring-opening pathway leading to polymerization.
Tanaka, Shinji,Nakashima, Takuya,Maeda, Toshie,Ratanasak, Manussada,Hasegawa, Jun-Ya,Kon, Yoshihiro,Tamura, Masanori,Sato, Kazuhiko
p. 1097 - 1103
(2018/02/14)

TRANSESTERIFICATION REACTION BY MEANS OF IRON CATALYST
Provided is a catalyst for transesterification reactions, which contains an iron salen complex. Also provided is a method for producing an ester compound, which is characterized by carrying out a transesterification reaction between a starting material ester and a starting material alcohol with use of the catalyst.
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Paragraph 0131-0133

(2017/10/10)

Synthesis of Esters by Functionalisation of CO2
The invention relates to a method for (I) producing a carboxylic ester of formula (I). Said method comprises the steps of: a) bringing an organosilane/borane of formula Si or B into contact with CO2, in the presence of a catalyst and an electrophilic compound of formula (III), the groups R1, R2, R3, R4, R5, Y, and M′ being as defined in claim 1; and optionally b) recovering the compound of formula (I) produced.
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Paragraph 0132

(2017/09/06)

Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio under solvent-free conditions
A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C-Br as well as CC and CC bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1.
Tang, Zhi,Jiang, Qiutao,Peng, Lifen,Xu, Xinhua,Li, Jie,Qiu, Renhua,Au, Chak-Tong
supporting information
p. 5396 - 5402
(2017/11/22)

Acid promoted C-C bond oxidative cleavage of β-O-4 and β-1 lignin models to esters over a copper catalyst
Depolymerisation of lignin to aromatics is a challenging task. We herein report that a Cu(OAc)2/BF3·OEt2 catalyst is effective in simultaneously cleaving C-C bonds in β-1 and β-O-4 ketones, yielding esters and phenols. In-depth studies show that C-H bond activation is the rate determining step for C-C bond cleavage. BF3·OEt2 promotes the reaction via activating the β-C-H bond. This study offers the potential to obtain aromatic esters from lignin.
Wang,Li,Lu,Li,Zhang,Liu,Luo,Wang
p. 702 - 706
(2017/08/15)

Hexyl triazabutadiene as a potent alkylating agent
Alkyl diazonium ions are among the most reactive alkylating agents in the synthetic chemists’ arsenal. That said, there are precious few methods by which one can selectively and safely utilize this chemistry. Herein, we show the use of a bench stable hexyl triazabutadiene as a source of reactive diazonium ions that undergo substitution chemistry with weak nucleophiles, such as carboxylates and even sulfonates. In the absence of a nucleophile, elimination was observed to occur. To overcome issues stemming from side-product inhibition of the reaction, we show that the triazabutadiene can be pre-activated with tosyl isocyanate.
Knyazeva, Diana C.,Kimani, Flora W.,Blanche, Jean-Laurent,Jewett, John C.
p. 2700 - 2702
(2017/06/23)

Highly Efficient Carbon Monoxide Capture by Carbanion-Functionalized Ionic Liquids through C-Site Interactions
A novel method for the highly efficient and reversible capture of CO in carbanion-functionalized ionic liquids (ILs) by a C-site interaction is reported. Because of its supernucleophilicity, the carbanion in ILs could absorb CO efficiently. As a result, a relatively high absorption capacity for CO (up to 0.046 mol mol?1) was achieved under ambient conditions, compared with CO solubility in a commonly used IL [Bmim][Tf2N] (2×10?3 mol mol?1). The results of quantum mechanical calculations and spectroscopic investigation confirmed that the chemical interaction between the C-site in the carbanion and CO resulted in the superior CO absorption capacities. Furthermore, the subsequent conversion of captured CO into valuable chemicals with good reactivity was also realized through the alkoxycarbonylation reaction under mild conditions. Highly efficient CO absorption by carbanion-functionalized ILs provides a new way of separating and converting CO.
Tao, Duan-Jian,Chen, Feng-Feng,Tian, Zi-Qi,Huang, Kuan,Mahurin, Shannon M.,Jiang, De-En,Dai, Sheng
supporting information
p. 6843 - 6847
(2017/06/06)

Iron-catalyzed C[sbnd]C bond activation/C[sbnd]O bond formation: Direct conversion of ketones to esters
The iron-catalyzed oxidative activation of the (O)C[sbnd]C bond in ketones has been developed. This method enables direct synthesis of esters by the reaction between ketones and alcohols via conversion of the (O)C[sbnd]C bond to the (O)C[sbnd]O bond. The
Arzumanyan, Ashot V.
supporting information
p. 4667 - 4671
(2017/11/21)

2,2,6,6-Tetramethylpiperidinium triflate (TMPT): a highly selective and self-separated catalyst for esterification
An eco-friendly and readily accessible 2,2,6,6-tetramethylpiperidinium triflate was found as highly-selective and self-separated catalyst for esterification under solvent-free condition. The X-ray crystallography revealed that it formed a ‘hydrophobic wall’ which could effectively eliminate the generated water from the reactive sites. Moreover, it could precipitate from the reaction system with excellent recovery ratio (>99%) and be reused for ten times without any significant loss of activity.
Gao, Lan,Liu, Taoping,Tao, Xiaochun,Huang, Yongmin
supporting information
p. 4905 - 4909
(2016/10/24)

Efficient and selective esterification of aromatic aldehydes with alcohols (1:1) using air as the simplest available oxidant and KCN
A new and efficient method is described for the oxidative esterification of aromatic aldehydes with different types of alcohols such as primary, secondary, benzylic, allylic and cyclic alcohols and phenols using air as the simplest available oxidant and potassium cyanide in DMF under neutral conditions in high yields. The present method esterifies aldehydes with alcohols in 1:1 molar ratio with excellent chemoselectivity and avoids the use of an external oxidant beside 02 from air.
Aghapour, Ghasem,Karimzadeh, Maryam
p. 1013 - 1018
(2017/11/10)

Gold-catalyzed selectivity-switchable oxidation of benzyl alcohol in the presence of molecular oxygen
A selectivity-switchable oxidation of benzyl alcohol by molecular oxygen is achieved with the iron doped graphene ([Formula presented]) supported gold catalysts. The oxidative esterification process is dominant with [Formula presented] and K2CO3 as the catalyst in methanol where a 96.2% conversion of benzyl alcohol and 99.9% selectivity of methyl benzoate were obtained. While, the oxidation of benzyl alcohol is orientated to produce benzaldehyde in n-butanol using [Formula presented] as the catalyst, in which an 89.1% conversion and 87.5% selectivity of benzaldehyde was attained. Moreover, the effects of the additive, reaction medium and reaction time were investigated. Also, the oxidation of different benzylic alcohols was successfully performed under the optimal conditions. Furthermore, the used catalysts were characterized by XRD, NH3-TPD, SEM, Roman, TG-DTA and BET techniques. Based on the experimental results and phenomena, a possible reaction mechanism is proposed for the selective oxidation of benzyl alcohol with molecular oxygen in which alkyl benzoate is produce through the hemiacetal intermediate of benzaldehyde with short chain alcohol, and the generation rate of hemiacetal decides the selectivity of product.
Sun, Jinyan,Tong, Xinli,Liu, Zonghui,Liao, Shengyun,Zhuang, Xuli,Xue, Song
p. 70 - 74
(2016/08/04)

Acid Chloride Synthesis by the Palladium-Catalyzed Chlorocarbonylation of Aryl Bromides
We report a palladium-catalyzed method to synthesize acid chlorides by the chlorocarbonylation of aryl bromides. Mechanistic studies suggest the combination of sterically encumbered PtBu3 and CO coordination to palladium can rapidly equilibrate the oxidative addition/reductive elimination of carbon-halogen bonds. This provides a useful method to assemble highly reactive acid chlorides from stable and available reagents, and can be coupled with subsequent nucleophilic reactions to generate new classes of carbonylated products. The Good, the Bad and the Bulky! By employing a sterically encumbered phosphine ligand, tri-tert-butyl phosphine, under palladium catalysis inert aryl bromides are chlorocarbonylated to create reactive acid chlorides by reversible carbon-halogen bond reductive elimination. This general platform allows for an expanded scope of the Heck carbonylation reaction to include previously incompatible nucleophiles.
Quesnel, Jeffrey S.,Kayser, Laure V.,Fabrikant, Alexander,Arndtsen, Bruce A.
supporting information
p. 9550 - 9555
(2015/06/30)

SO3H and NH2+ functional carbon-based solid acid catalyzed transesterification and biodiesel production
A SO3H and NH2+ functional carbon-based solid acid was used as a highly active heterogeneous catalyst for the transesterification of various carboxylic methyl esters with alcohols under mild conditions. It also showed high catalytic performance for transesterification of triolein with methanol or isopropanol. Furthermore, it was able to catalyze simultaneous esterification and transesterification of rice oil and butter respectively, the yields of biodiesel obtained were up to 94%, and the catalyst could be easily recovered and reused more than ten times without loss of activity, which indicated the carbon-based solid acid was a potential catalyst for the biodiesel industry.
Cai, Liangzhen,Meng, Decai,Zhan, Shaoqi,Yang, Xiaoxia,Liu, Taoping,Pu, Huiming,Tao, Xiaochun
p. 72146 - 72149
(2015/09/08)

The carbon material functionalized with NH2+ and SO3H groups catalyzed esterification with high activity and selectivity
A novel carbon-based solid acid was conveniently prepared by heating a mixture of d-glucose, p-toluenesulfonic acid and diphenylammonium tosylate. Its structure was measured by XRD, FT-IR, XPS, 13C MAS NMR and EA to illustrate that the carbon material has been functionalized with NH2+ and SO3H groups and has a strong "hydrophobic effect". It can be used to catalyze the esterification reaction of carboxylic acids with equimolar amounts of sterically demanding and acid-sensitive alcohols with high reactivity (yield up to 90%) and selectivity (up to 95%) in heptane at 80 °C. It could be easily recovered and reused more than ten times without loss of activity.
Zhan, Shaoqi,Tao, Xiaochun,Cai, Liangzhen,Liu, Xiaohui,Liu, Taoping
supporting information
p. 4649 - 4653
(2015/02/19)

Graphite oxide as an efficient solid reagent for esterification reactions
Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.
Mirza-Aghayan, Maryam,Rahimifard, Mahshid,Boukherroub, Rabah
p. 859 - 864
(2014/12/10)

Versatile and sustainable alcoholysis of amides by a reusable CeO 2 catalyst
CeO2 catalyzed the esterification between an equivalent molar ratio of primary amides and alcohols under neutral conditions, which provides the first versatile reusable catalytic system for direct alcoholysis of amides to esters with wider scope and 67 times higher turnover number (TON) than previous catalytic systems.
Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Tamura, Masazumi,Shimizu, Ken-Ichi
p. 35803 - 35807
(2014/11/07)

Facile esterification of carboxylic acid using amide functionalized benzimidazolium dicationic ionic liquids
Herein, we report the synthesis of a new series of amide functionalized dicationic benzimidazolium based ionic liquids (DBimILs) and appraised their efficacy towards perceptive esterification of carboxylic acids with alkyl/allyl/aryl halides in presence of triethylamine. The amide groups present in this new series of DBimILs are expected to form hydrogen bonding with the carboxylic acids and this could facilitate the esterification reactions under mild conditions devoid of any added catalyst or organic solvent. The plausible mechanism for the enhanced catalytic activity in presence of this new series of ILs has been proposed. The corresponding alkyl/allyl/aryl esters isolated from this reaction were of high purity after simple extraction, which wipe out the necessity for further purification. This protocol addresses clean methodology and the efficient recyclability as well as reusability of the catalyst.
Muskawar, Prashant Narayan,Thenmozhi,Gajbhiye, Jayant M.,Bhagat, Pundlik Rambhau
p. 214 - 220
(2014/07/08)

TRANSITION METAL CATALYSTS FOR HYDROGENATION AND HYDROSILYLATION
Phosphoranimide-metal catalysts and their role in hydrogenation and hydrosilylation are disclosed. The catalysts comprise first row transition metals such as nickel, cobalt or iron. The catalysts have a metal to anionic phosphoranimide ratio of 1:1. This disclosure presents a process for catalytic hydrogenation and hydrosilylation of a range of unsaturated organic compounds under lower temperature and pressure conditions than conditions associated with industrial hydrogenation and hydrosilylation.
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Paragraph 0128

(2014/07/08)

A facile and efficient protocol for esterification and acetalization in a PEG1000-D(A)IL/toluene thermoregulated catalyst-media combined systems
A novel efficient and recyclable temperature-dependent biphasic catalyst and reaction media combined system comprised of PEG-1000 linked dicationic acidic ionic liquid and toluene was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes with good to excellent yields. This system is characteristic of temperature-dependent reversible biphasic property, simple and facile recyclability, high catalytic activity and extensive substrate and reaction adaptability.
Wang, Yinglei,Zhi, Huizhen,Luo, Jun
p. 46 - 52
(2013/09/23)

Catalysis studies of macroreticular polystyrene cation-exchange resin with terminal perfluoroalkanesulfonic acids
Macroreticular p-(ω-sulfonic-perfluoroalkylated) polystyrene (FPS) resin with the advantages of both sulfonic polystyrene (such as macroreticular Amberlyst-15) and perfluoroalkanesulfonic resin (such as superacidic Nafion NR50) has exhibited excellent catalytic selectivity and activity in cyclization of pseudoionone and condensation of indole. In this paper, FPS was characterized by XPS, nitrogen sorption technique, FESEM and Hammett indicator method, and employed as the solid acid catalyst in the esterification, acylation and alkylation reactions. The FPS resin showed better activity than commercial solid acid catalysts (Amberlyst-15 and Nafion NR50) owing to its high surface area and strong acidity close to superacidity.
Lin, Zhenghuan,Guan, Chuanjin,Huang, Limei,Wang, Wen,Ling, Qidan,Zhao, Chengxue
p. 261 - 266
(2013/07/27)

CeO2 as a versatile and reusable catalyst for transesterification of esters with alcohols under solvent-free conditions
CeO2 acted as an efficient and reusable heterogeneous catalyst for transesterification of esters with alcohols under the solvent-free conditions at 160 °C. Among the 11 kinds of metal oxides, CeO2 is the most suitable catalyst in terms of catalytic activity, leaching-resistance and reusability. This catalytic system tolerates various esters and alcohols, and valuable esters such as heteroaromatic esters and benzyl benzoates are produced, demonstrating a practical utility of the system. On the basis of kinetic analysis and in situ IR studies of adsorbed species, a reaction mechanism is proposed, in which proton abstraction of alcohol by a Lewis base site of CeO2 to yield alkoxide species is the rate-limiting step.
Tamura, Masazumi,Hakim Siddiki,Shimizu, Ken-Ichi
p. 1641 - 1646
(2013/09/24)

Mild and efficient capture and functionalisation of CO2 using silver(i) oxide and application to 13C-labelled dialkyl carbonates
A high yielding three-component reaction between β-iodo ethylamine derivatives, MeOH and gaseous CO2 at ambient temperatures and pressures is reported using silver(i) oxide. Unfunctionalised alkyl iodides were also found to be effective in this transformation and their optimisation is also described. To highlight the ease and control with which gaseous CO 2 can be captured and functionalised under mild conditions, the reaction was performed using 13C-enriched CO2 to afford specifically 13C-carbonyl-labelled dialkyl carbonates with exquisite control of the isotopic purity in good yields and without the need for specialised equipment.
Tunbridge, Gemma A.,Baruchello, Riccardo,Caggiano, Lorenzo
p. 4613 - 4621
(2013/05/08)

Selective oxidation of alcohols to esters using heterogeneous Co 3O4-N@C catalysts under mild conditions
Novel cobalt-based heterogeneous catalysts have been developed for the direct oxidative esterification of alcohols using molecular oxygen as benign oxidant. Pyrolysis of nitrogen-ligated cobalt(II) acetate supported on commercial carbon transforms typical homogeneous complexes to highly active and selective heterogeneous Co3O4-N@C materials. By applying these catalysts in the presence of oxygen, the cross and self-esterification of alcohols to esters proceeds in good to excellent yields.
Jagadeesh, Rajenahally V.,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Brueckner, Angelika,Beller, Matthias
supporting information
p. 10776 - 10782
(2013/08/23)

Oxidation of acyclic alkenes and allyl and benzyl ethers with DIB/t-BuOOH/Mg(OAc)2
Oxidation of (11Z)-1′,2′-didehydrostemofoline with DIB/TBHP/Mg(OAc)2·4H2O resulted in oxidative cleavage of the C-11-C-12 double bond instead of the desired allylic oxidation of the 1-butenyl side chain. Stemofoline gave a similar result. The oxidation of more simple terminal alkenes was regioselective and gave vinyl ketones while allyl and benzyl ethers gave acrylate and benzoate esters, respectively. Allyl and benzyl ethers could be chemoselectively oxidized in the presence of a terminal alkene or benzyl group. Oxidation of an internal alkene was poorly regioselective, in contrast to the oxidation of 1-substituted cyclohexenes.
Sastraruji, Thanapat,Pyne, Stephen G.,Ung, Alison T.
experimental part
p. 598 - 602
(2012/01/05)

Preparation, characterisation and evaluation of brazilian clay-based catalysts for use in esterification reactions
Natural Brazilian clay-based catalysts were prepared, characterised, and their catalytic activity was assessed in esterification reactions. The natural clays were acid activated as received, without any previous treatment. Both natural and acid-activated clays were characterised by XRD, NH3-TPD, thermodesorption of n-butylamine, N2 adsorption analysis, FT-IR, TGA and DTA. The catalytic performance was investigated in the esterification of several carboxylic acids with different alcohols. The reactions were carried out in a 1:3 carboxylic acid/alcohol molar ratio at 100 °C and atmospheric pressure for 3h. The acid-activated clays provided good yields and better performance than commercial clay K10.
Rezende, Michelle J. C.,Pereira, Mi?rian S. C.,Santos, Gabriel F. N.,Aroeira, Gabriel O. P.,Albuquerque Jr., Tiago C.,Suarez, Paulo A. Z.,Pinto, Angelo C.
experimental part
p. 1209 - 1215
(2012/10/08)

General and selective palladium-catalyzed oxidative esterification of alcohols
Selectively esterified: Primary alcohols react with dioxygen as a benign oxidant in a palladium-catalyzed oxidative esterification (see scheme). The corresponding aldehydes and esters are formed highly selectively depending on the catalyst system. The reactions take place in the presence of commercially available ligands without the need for additional organic hydrogen acceptors. Copyright
Gowrisankar, Saravanan,Neumann, Helfried,Beller, Matthias
supporting information; experimental part
p. 5139 - 5143
(2011/06/25)

ACYLATION REACTION OF HYDROXYL GROUP
Disclosed is a selective ester production process of an alcoholic hydroxyl group, which proceeds under chemically mild conditions, while having adequate environmental suitability, operability and economical efficiency. Specifically disclosed is a process for producing an ester compound, which is characterized in that an alcohol and a carboxylic acid ester compound are reacted in the presence of a compound containing zinc element, thereby selectively acylating a hydroxyl group of the alcohol.
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Page/Page column 15; 17

(2010/07/03)

An experimental-theoretical study of the factors that affect the switch between ruthenium-catalyzed dehydrogenative amide formation versus amine alkylation
A ruthenium(II) diamine complex can catalyze the intramolecular cyclization of amino alcohols H2N(CH2)nOH via two pathways: (i) one yields the cyclic secondary amine by a redox-neutral hydrogen-borrowing route with loss of water; and (ii) the second gives the corresponding cyclic amide by a net oxidation involving loss of H2. The reaction is most efficient in cases where the product has a six-membered ring. The amide and amine pathways are closely related: DFT calculations show that both amine and amide formations start with the oxidation of the amino alcohol, 5-amino-1-pentanol, to the corresponding amino aldehyde, accompanied by reduction of the catalyst. The intramolecular condensation of the amino aldehyde takes place either in the coordination sphere of the metal (path I) or after dissociation from the metal (path II). Path I yields the Ru-bound zwitterionic form of the hemiaminal protonated at nitrogen, which eliminates H2, forming the amide product. In path II, the free hemiaminal dehydrates, giving an imine, which yields the amine product by hydrogenation with the reduced form of the catalyst generated in the initial amino alcohol oxidation. For amide to be formed, the hemiaminal must remain metal-bound in the key intermediate and the elimination of H2 must occur from the same intermediate to provide a vacant site for β-elimination. The elimination of H2 is affected by an intramolecular H-bond in the key intermediate. For amine to be formed, the hemiaminal must be liberated for dehydration to imine and the H2 must be retained on the metal for reduction of the imine intermediate.
Nova, Ainara,Balcells, David,Schley, Nathan D.,Dobereiner, Graham E.,Crabtree, Robert H.,Eisenstein, Odile
experimental part
p. 6548 - 6558
(2011/02/17)

Reactivity of anionic nucleophiles in ionic liquids and molecular solvents
The nucleophilic reactivity of a representative series of anions has been measured in [hmim][ClO4] 3i, [hm2im][ClO4] 3′i, and [hmim][PF6] 3l ILs in the reaction with n-alkyl methanesulfonates and compared with that found in common molecular solvents (MeOH, DMSO, PhCl). The reactivity is found to depend on both the imidazolium cation-anion interaction and the specific solvation by water present in the IL, the water playing the main effect, in particular with hydrophilic anions. Removal of the largest quantity of water remarkably increases the ion pair reactivity in the IL up to rate constant value k comparable with those obtained in DMSO and in low polarity media (PhCl).
Betti, Cecilia,Landini, Dario,Maia, Angelamaria
p. 1689 - 1695
(2008/09/18)