Transketolase and fructose-1,6-bis-phosphate aldolase, complementary tools for access to new ulosonic acid analogues
摘要:
A new approach to the synthesis of ulosonic acids KDO and DAH is described. The key step is the C-5-C-6 bond formation catalysed by fructose-1,6-bisphosphate aldolase (for KDO) or transketolase (for DAH) using substituted acrylonitrile alpha-hydroxyaldehyde. All asymmetric carbon configurations are determined in an enzymatic step by the means of deshydrogenase or lipase. This strategy, using a non-metabolism pathway, allows access to novel precursors of KDO, DAH and analogues. (C) 2004 Elsevier Ltd. All rights reserved.
Chemoenzymatic synthesis of chiral substituted acrylate and acrylonitrile precursors for the synthesis of 3-deoxy-2-ulosonic acids and α-methylene-γ-lactones
摘要:
Substituted acrylonitrile and ethyl acrylate bearing a masked alpha -hydroxyaldehyde were easily synthesised by a Barbier type reaction between the monoacetal of glyoxal and bromomethyl acrylonitrile or ethyl bromomethyl acrylate. We prepared these interesting synthons in an enantiomerically pure form by enzymatic resolution with Candida rugosa lipase. or by microbial reduction of the corresponding ketones using Aspergillus niger and Lactobacillus kefir. (C) 2001 Elsevier Science Ltd. All rights reserved.