- A solvent-reagent selection guide for Steglich-type esterification of carboxylic acids
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The Steglich esterification is a widely employed method for the formation of esters under mild conditions. A number of issues regarding the sustainability of this transformation have been identified, chiefly the use of hazardous carbodiimide coupling reagents in conjunction with solvents with considerable issues such as dichloromethane (DCM) and N,N-dimethylformamide (DMF). To overcome these issues, we have developed a solvent-reagent selection guide for the formation of esters via Steglich-type reactions with the aim of providing safer, more sustainable conditions. Optimum reaction conditions have been identified after high-throughput screening of solvent-reagent combinations, namely the use of Mukaiyama's reagent (Muk) in conjunction with solvent dimethyl carbonate (DMC). The new reaction conditions were also exemplified through the synthesis of a small selection of building-block like molecules and includes the formation of t-butyl esters.
- Jordan, Andrew,Sneddon, Helen F.,Sydenham, Jack,Whymark, Kyran D.
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supporting information
p. 6405 - 6413
(2021/09/10)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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- Preparation of Organic Nitrates from Aryldiazoacetates and Fe(NO3)3·9H2O
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A thermal protocol is reported for the formal insertion of nitric acid into aryldiazoacetates using Fe(NO3)3·9H2O. This strategy is mild and high yielding and allows the preparation of a large variety of members of an unprecedented family of organic nitrates. The nitrate group can be also readily transformed into other functional groups and heterocyclic moieties and can possibly allow new biological explorations of untapped potential associated with their NO-releasing ability.
- Thurow, Samuel,Fernandes, Alessandra A. G.,Quevedo-Acosta, Yovanny,De Oliveira, Matheus F.,De Oliveira, Marcelo G.,Jurberg, Igor D.
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supporting information
p. 6909 - 6913
(2019/09/12)
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- Palladium-Catalyzed Decarboxylative Carbonylative Transformation of Benzyl Aryl Carbonates: Direct Synthesis of Aryl 2-Arylacetates
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A procedure on palladium-catalyzed decarboxylative alkoxycarbonylation of carbonates for the synthesis of aryl 2-arylacetates has been developed. A broad range of aryl 2-arylacetates were obtained in good yields under mild conditions under a carbon monoxide atmosphere. Interestingly, other alcohols can be added as nucleophiles as well, and the corresponding esters were also obtained in good yields.
- Xu, Jian-Xing,Wu, Xiao-Feng
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p. 5938 - 5941
(2018/09/21)
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- Palladium-catalyzed carbonylation of benzylic ammonium salts to amides and esters: Via C-N bond activation
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An efficient palladium-catalyzed carbonylation reaction of readily available quaternary ammonium salts with CO is reported for the first time to afford arylacetamides and arylacetic acid esters via benzylic C-N bond cleavage. This protocol features mild reaction conditions under atmospheric pressure of CO, a redox-neutral process without an additional oxidant, and a broad substrate scope for various kinds of amines, alcohols and phenols.
- Yu, Weijie,Yang, Shuwu,Xiong, Fei,Fan, Tianxiang,Feng, Yan,Huang, Yuanyuan,Fu, Junkai,Wang, Tao
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supporting information
p. 3099 - 3103
(2018/05/22)
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- Ni-Catalyzed chemoselective alcoholysis of: N -acyloxazolidinones
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Although N-acyloxazolidinone-based (catalytic) asymmetric synthetic methodologies occupy an important position in modern organic synthesis, the catalytic cleavage of a chiral auxiliary remains underdeveloped. We report the Ni(cod)2/bipyr.-catalyzed alcoholysis of N-acyloxazolidinones to deliver esters. The reaction is broad in scope for both N-acyloxazolidinone substrates and alcohol nucleophiles, and displays good functional group tolerance and excellent chemoselectivity. A gram-scale methanolysis allowed the enantioselective synthesis of the C22-C26 segment of a close analogue of the potent immunosuppressant agent FK506.
- Huang, Pei-Qiang,Geng, Hui
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supporting information
p. 593 - 599
(2018/02/14)
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- 2,2,6,6-Tetramethylpiperidinium triflate (TMPT): a highly selective and self-separated catalyst for esterification
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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
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supporting information
p. 4905 - 4909
(2016/10/24)
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- SO3H and NH2+ functional carbon-based solid acid catalyzed transesterification and biodiesel production
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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
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p. 72146 - 72149
(2015/09/08)
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- The carbon material functionalized with NH2+ and SO3H groups catalyzed esterification with high activity and selectivity
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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
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supporting information
p. 4649 - 4653
(2015/02/19)
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- A lewis acid-promoted pinner reaction
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Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
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supporting information
p. 1572 - 1577
(2013/10/22)
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- Preparation, characterisation and evaluation of brazilian clay-based catalysts for use in esterification reactions
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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.
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experimental part
p. 1209 - 1215
(2012/10/08)
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- Ligand-assisted rate acceleration in lanthanum
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The transesterification of an equimolar mixture of carboxylic esters and primary (1°), secondary (2°), and tertiary (3°) alcohols in hydrocarbon solvents was promoted with high efficiency by a lanthanum(III) complex, which was prepared in situ from lanthanum (III) isopropoxide (1 mol %) and 2-(2-methoxyethoxy)ethanol (2 mol %). The present La(III) catalyst was highly effective for the chemoselective transesterification in the presence of competitive 1°-and 2°-amines. Remarkably, esters were obtained in good to excellent yields as colorless materials without an inconvenient workup procedure.
- Hatano, Manabu,Furuya, Yoshiro,Shimmura, Takumi,Moriyama, Katsuhiko,Kamiya, Sho,Maki, Toshikatsu,Ishihara, Kazuaki
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supporting information; experimental part
p. 426 - 429
(2011/04/15)
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- Bronsted acid catalyzed addition of phenols, carboxylic acids, and tosylamides to simple olefins
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(Chemical Equation Presented) Intermolecular addition of phenols, carboxylic acids, and protected amines to inert olefins can be catalyzed by low concentrations (1-5%) of triflic acid. Functional groups, such as the methoxyl substitution on aromatics, could be tolerated if the concentration of triflic acid and the reaction temperature are controlled appropriately. This reaction provides one of the simplest olefin addition methods and is an alternative to metal-catalyzed reactions.
- Li, Zigang,Zhang, Junliang,Brouwer, Chad,Yang, Cai-Guang,Reich, Nicholas W.,He, Chuan
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p. 4175 - 4178
(2007/10/03)
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- Gold(I)-catalyzed intermolecular addition of phenols and carboxylic acids to olefins
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Ph3PAuOTf can catalyze efficient intermolecular addition of phenols and carboxylic acids to olefins under relatively mild conditions. Copyright
- Yang, Cai-Guang,He, Chuan
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p. 6966 - 6967
(2007/10/03)
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- Oxidation of Alkynes by Hydrogen Peroxide Catalyzed by Methylrhenium Trioxide
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The oxidation of alkynes with hydrogen peroxide is catalyzed by methylrhenium tioxide.The reactions can be rationalized by postulating that an oxirene intermediate is formed between a rhenium peroxide and the alkyne.Internal alkynes yield α-diketones and carboxylic acids, the latter from the complete cleavage of the triple bonds.Rearrangement products were observed only for aliphatic alkynes.Terminal alkynes gave carboxylic acids and their derivatives and α-keto acids as the major products, but their yields varied with the solvent used.
- Zhu, Zuolin,Espenson, James H.
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p. 7728 - 7732
(2007/10/03)
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- A novel, general route to the synthesis of carboxylic acid esters and thiolesters
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Carboxylic acids were conveniently esterified with alcohols and thiols by the use of triphenylphosphine and N-bromo/Iodo succinimide to afford the corresponding esters and thiol esters.
- Sucheta,Reddy,Ravi,Rama Rao
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p. 4415 - 4416
(2007/10/02)
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- Preparation and Characterization of 6-Substituted 1,8-diazabicycloundec-7-ene
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The lithium 1,8-diazabicycloundec-6-ide (1) prepared from 1,8-diazabicycloundec-7-ene (DBU) and n-butyllithium reacts with alkyl halides and carbonyl compounds such as benzophenone, acetophenone, and benzaldehyde to give 6-substituted DBU derivatives in good yields.The reaction behavior of 6-substited DBU was also investigated.
- Matsumura, Noburu,Nishiguchi, Hiroshi,Okada, Masao,Yoneda, Shigeo
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p. 885 - 887
(2007/10/02)
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