The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Thierry Maugard - One of the best experts on this subject based on the ideXlab platform.
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Kinetic study of 2-butanol O-Acylation and sec-butylamine N-Acylation catalyzed by Candida antarctica lipase B
Journal of Molecular Catalysis B: Enzymatic, 2011Co-Authors: Florian Le Joubioux, A. Oussama, Nicolas Bridiau, Marianne Graber, Thierry MaugardAbstract:The aim of this work was to study the differential behavior shown by Candida antarctica lipase B during the O-Acylation and N-Acylation of monofunctional alcohols and monofunctional amines. To achieve this, 2-butanol and sec-butylamine were used as model molecules. Yields, kinetics and enantioselectivity were studied for both reactions. Although a steady-state ordered ternary complex bi-bi mechanism was obtained for the O-Acylation of 2- butanol, a ping-pong bi-bi mechanism was obtained for the N-Acylation in case of low sec- butylamine concentrations. The values of apparent kinetics parameters were calculated: the enantiomeric ratios (E) were evaluated and confirmed the preference of Candida antarctica lipase B for the (R)-enantiomer, which was consistent with the literature. The nantioselectivity was calculated for the alcohol (E ≈ 3.17) and for the amine (E ≈ 1.34). Concerning the O-Acylation, the yields were found to be very similar for both enantiomers R and S. However, both initial rates and yields of the (R)-enantiomer N-Acylation were higher than those of the (S)-enantiomer. In the last part of our study, the chemoselectivity of Candida antarctica lipase B was evaluated, showing that Candida antarctica lipase B was a chemoselective enzyme that preferentially catalyzed the O-Acylation to the detriment of the N-Acylation (C ≈ 92, for the selective Acylation of (R)-enantiomers). These results provide new insights for the synthesis of products issued from the selective Acylation of multifunctional substrates such as amino-alcohols.
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Kinetic study of 2-butanol O-Acylation and sec-butylamine N-Acylation catalyzed by Candida antarctica lipase B
Journal of Molecular Catalysis B: Enzymatic, 2011Co-Authors: Florian Le Joubioux, Nicolas Bridiau, Marianne Graber, Oussama Achour, Thierry MaugardAbstract:The aim of this work was to study the differential behavior shown by Candida antarctica lipase B during the O-Acylation and N-Acylation of monofunctional alcohols and monofunctional amines. To achieve this, 2-butanol and sec-butylamine were used as model molecules. Yields, kinetics and enantioselectivity were studied for both reactions. Although a steady-state ordered ternary complex bi-bi mechanism was obtained for the O-Acylation of 2-butanol, a ping-pong bi-bi mechanism was obtained for the N-Acylation in case of low sec-butylamine concentrations. The values of apparent kinetic parameters were calculated: the enantiomeric ratios (E) were evaluated and confirmed the preference of C. antarctica lipase B for the (R)-enantiomer, which was consistent with the literature. The enantioselectivity was calculated for the alcohol (E ≈ 3.17) and for the amine (E ≈ 1.34). Concerning the O-Acylation, the yields were found to be very similar for both enantiomers R and S. However, both initial rates and yields of the (R)-enantiomer N-Acylation were higher than those of the (S)-enantiomer. In the last part of our study, the chemoselectivity of C. antarctica lipase B was evaluated, showing that C. antarctica lipase B was a chemoselective enzyme that preferentially catalyzed the O-Acylation to the detriment of the N-Acylation (C ≈ 92, for the selective Acylation of (R)-enantiomers). These results provide new insights for the synthesis of products issued from the selective Acylation of multifunctional substrates such as amino-alcohols.
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Kinetic study of 2-butanol O-Acylation and sec-butylamine N-Acylation catalyzed by Candida antarctica lipase B
Journal of Molecular Catalysis B: Enzymatic, 2011Co-Authors: Florian Le Joubioux, Nicolas Bridiau, Marianne Graber, Oussama Achour, Thierry MaugardAbstract:International audienceThe aim of this work was to study the differential behavior shown by Candida antarctica lipase B during the O-Acylation and N-Acylation of monofunctional alcohols and monofunctional amines. To achieve this, 2-butanol and sec-butylamine were used as model molecules. Yields, kinetics and enantioselectivity were studied for both reactions. Although a steady-state ordered ternary complex bi-bi mechanism was obtained for the O-Acylation of 2-butanol, a ping-pong bi-bi mechanism was obtained for the N-Acylation in case of low sec-butylamine concentrations. The values of apparent kinetic parameters were calculated: the enantiomeric ratios (E) were evaluated and confirmed the preference of C. antarctica lipase B for the (R)-enantiomer, which was consistent with the literature. The enantioselectivity was calculated for the alcohol (E ≈ 3.17) and for the amine (E ≈ 1.34). Concerning the O-Acylation, the yields were found to be very similar for both enantiomers R and S. However, both initial rates and yields of the (R)-enantiomer N-Acylation were higher than those of the (S)-enantiomer. In the last part of our study, the chemoselectivity of C. antarctica lipase B was evaluated, showing that C. antarctica lipase B was a chemoselective enzyme that preferentially catalyzed the O-Acylation to the detriment of the N-Acylation (C ≈ 92, for the selective Acylation of (R)-enantiomers). These results provide new insights for the synthesis of products issued from the selective Acylation of multifunctional substrates such as amino-alcohols
Wangke Qian - One of the best experts on this subject based on the ideXlab platform.
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microwave assisted one step synthesis of acetophenones via palladium catalyzed regioselective arylation of vinyloxytrimethylsilane
ChemInform, 2013Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:Employing vinyloxytrimethylsilane (II) as a novel Acylation reagent in the Heck arylation generates acetophenones in good to high yields from aryl iodides under microwave irradiation in a single step.
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Microwave‐Assisted One‐Step Synthesis of Acetophenones via Palladium‐Catalyzed Regioselective Arylation of Vinyloxytrimethylsilane.
ChemInform, 2013Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:Employing vinyloxytrimethylsilane (II) as a novel Acylation reagent in the Heck arylation generates acetophenones in good to high yields from aryl iodides under microwave irradiation in a single step.
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microwave assisted one step synthesis of acetophenones via palladium catalyzed regioselective arylation of vinyloxytrimethylsilane
Advanced Synthesis & Catalysis, 2012Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:The regiochemistry of the palladium-mediated arylation (Heck arylation) of enol ethers is sensitive to the structure of the enol ether, the arylating agent and the catalytic system. In this study, an effective and practical method was successfully developed for the synthesis of acetophenones with high regioselectivity under palladium-catalyzed conditions. A variety of acetophenones was readily prepared from aryl iodides in good to excellent yields under microwave irradiation in a single step. The key feature of our new protocol is the use of vinyloxytrimethylsilane as a highly regioselective Acylation reagent.
Jianliang Xiao - One of the best experts on this subject based on the ideXlab platform.
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Double Arylation of Allyl Alcohol via a One‐Pot Heck Arylation—Isomerization—Acylation Cascade.
ChemInform, 2012Co-Authors: Paul Colbon, Mark Purdie, Keith Molholland, Jiwu Ruan, Jianliang XiaoAbstract:The arylation step favors aryl bromides bearing electron-withdrawing substituents, while the Acylation reaction is supported by electron-donating groups.
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double arylation of allyl alcohol via a one pot heck arylation isomerization Acylation cascade
Organic Letters, 2011Co-Authors: Paul Colbon, Mark Purdie, Jiwu Ruan, Keith R Mulholland, Jianliang XiaoAbstract:A one-pot, two-step catalytic protocol has been developed. A regioselective Heck coupling between aryl bromides and allyl alcohol leads to the generation of arylated allyl alcohols that in situ isomerize to give aldehydes, which then undergo an Acylation reaction with a second aryl bromide. A variety of aryl bromides can be employed in both the initial Heck reaction and the Acylation, providing easy access to a wide variety of substituted dihydrochalcones.
Sung Gak Kim - One of the best experts on this subject based on the ideXlab platform.
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free radical mediated Acylation and carboxylation reactions
Advanced Synthesis & Catalysis, 2004Co-Authors: Sung Gak KimAbstract:Radical Acylations to prepare carbonyl compounds are described and focus on indirect Acylation approaches using sulfonyl oxime ethers under tin-mediated and tin-free conditions. The efficiency of carboxylic acid derivatives as carbonyl group radical acceptors in radical Acylation and carboxylation reactions is discussed.
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Free Radical‐Mediated Acylation and Carboxylation Reactions
Advanced Synthesis & Catalysis, 2004Co-Authors: Sung Gak KimAbstract:Radical Acylations to prepare carbonyl compounds are described and focus on indirect Acylation approaches using sulfonyl oxime ethers under tin-mediated and tin-free conditions. The efficiency of carboxylic acid derivatives as carbonyl group radical acceptors in radical Acylation and carboxylation reactions is discussed.
Hong Liu - One of the best experts on this subject based on the ideXlab platform.
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microwave assisted one step synthesis of acetophenones via palladium catalyzed regioselective arylation of vinyloxytrimethylsilane
ChemInform, 2013Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:Employing vinyloxytrimethylsilane (II) as a novel Acylation reagent in the Heck arylation generates acetophenones in good to high yields from aryl iodides under microwave irradiation in a single step.
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Microwave‐Assisted One‐Step Synthesis of Acetophenones via Palladium‐Catalyzed Regioselective Arylation of Vinyloxytrimethylsilane.
ChemInform, 2013Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:Employing vinyloxytrimethylsilane (II) as a novel Acylation reagent in the Heck arylation generates acetophenones in good to high yields from aryl iodides under microwave irradiation in a single step.
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microwave assisted one step synthesis of acetophenones via palladium catalyzed regioselective arylation of vinyloxytrimethylsilane
Advanced Synthesis & Catalysis, 2012Co-Authors: Wangke Qian, Lei Zhang, Haifeng Sun, Hualiang Jiang, Hong LiuAbstract:The regiochemistry of the palladium-mediated arylation (Heck arylation) of enol ethers is sensitive to the structure of the enol ether, the arylating agent and the catalytic system. In this study, an effective and practical method was successfully developed for the synthesis of acetophenones with high regioselectivity under palladium-catalyzed conditions. A variety of acetophenones was readily prepared from aryl iodides in good to excellent yields under microwave irradiation in a single step. The key feature of our new protocol is the use of vinyloxytrimethylsilane as a highly regioselective Acylation reagent.
