Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones
摘要:
A catalytic regio- and enantioselective aldol reaction of various unsymmetrical methyl ketones with para-nitrobenzaldehyde has been developed using aldolase antibodies as the catalysts. It has been found that the sense and level of regioselectivity for the reactions catalysed by antibody 38C2 and 33F12 are highly dependent on the structure of both the donor and the acceptor but in contrast, antibodies 84G3 and 93F3 catalyse the exclusive formation of the linear regioisomer independent of the structure of the reactants examined. The level of enantiocontrol is very high for most reactions. Both linear aldol enantiomers could be accessed through aldol or retro-aldol reactions using the same antibody. Theoretical studies on regioisomeric alpha- and beta-heteroatom substituted enamines derived from unsymmetrical ketones suggest that most of the linear aldol products formed in the presence of antibodies 84G3 and 93F3 must be formed from intermediate enamines which are not the thermodynamically most favourable. (C) 2003 Elsevier Ltd. All rights reserved.
Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones
摘要:
A catalytic regio- and enantioselective aldol reaction of various unsymmetrical methyl ketones with para-nitrobenzaldehyde has been developed using aldolase antibodies as the catalysts. It has been found that the sense and level of regioselectivity for the reactions catalysed by antibody 38C2 and 33F12 are highly dependent on the structure of both the donor and the acceptor but in contrast, antibodies 84G3 and 93F3 catalyse the exclusive formation of the linear regioisomer independent of the structure of the reactants examined. The level of enantiocontrol is very high for most reactions. Both linear aldol enantiomers could be accessed through aldol or retro-aldol reactions using the same antibody. Theoretical studies on regioisomeric alpha- and beta-heteroatom substituted enamines derived from unsymmetrical ketones suggest that most of the linear aldol products formed in the presence of antibodies 84G3 and 93F3 must be formed from intermediate enamines which are not the thermodynamically most favourable. (C) 2003 Elsevier Ltd. All rights reserved.
Acrylic resin immobilized Candida antarctica lipase B (CAL-B) is able to catalyse decarboxylative aldol reaction and decarboxylative Knoevenagel reaction with good to excellent yields.
One-pot bienzymatic cascade combining decarboxylative aldol reaction and kinetic resolution to synthesize chiral β-hydroxy ketone derivatives
作者:Fan Xu、Jian Xu、Yujing Hu、Xianfu Lin、Qi Wu
DOI:10.1039/c6ra12729k
日期:——
bienzymatic one-potsequential cascade for the synthesis of (S)-β-hydroxy ketones and acylated (R)-β-hydroxy ketone derivatives was successfully developed. An immobilized lipase from Mucor miehei (MML) catalysed promiscuous decarboxylative aldol reaction and a lipase A or B from Candida antarctica (CAL-A or CAL-B) catalysed kinetic resolution of racemic β-hydroxy ketone were combined in this one-pot protocol
Catalytic antibody 27C1 bears binding sites for both a substrate-and a functionalized small nonprotein component in the active site. We investigated the possibility of exploiting imine and enamine intermediates using a primary amine molecule into the active site of antibody 27C1. The antibody catalyzed beta-keto acid decarboxylation with a rate enhancement (k(cat)/K-m/k(uncat)) of 140,000, as well as highly regioselective cross-aldol reactions of ketones and p-nitrobenzaldehyde. These studies provide new strategies for the generation of catalytic antibodies possessing binding sites for functionalized components. (C) 2013 Elsevier Ltd. All rights reserved.
Mahajan, Dinesh; Chimni, Swapandeep Singh, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2007, vol. 46, # 8, p. 1355 - 1358
作者:Mahajan, Dinesh、Chimni, Swapandeep Singh
DOI:——
日期:——
Unprecedented Regiocontrol Using An Aldolase I Antibody