enhancement: The X‐ray crystal structure of an arylmalonatedecarboxylase (AMDase) with a mechanism‐based inhibitor bound to an active‐site dioxyanion hole provides insight into the mechanism of this intriguing enzyme. The structure also guided the extension of the AMDase biocatalytic repertoire to include a wide range of α‐alkenyl as well as α‐arylmalonates.
A new preparation of 3,5,5-trialkyl-gamma-butyrolactones of defined absolute configuration is reported. This method involves the diastereoselective alkylation of 3,4-ethylenic acids after incorporation of a chiral Evans auxiliary, and then after separation of the two diastereomers and hydrolysis of the auxiliary, stereospecific halo lactonizations. This method was applied to the preparation of a natural product, present in a sponge. (c) 2007 Elsevier Ltd. All rights reserved.
Chemoenzymatic Cascade Synthesis of Optically Pure Alkanoic Acids by Using Engineered Arylmalonate Decarboxylase Variants
Arylmalonatedecarboxylase (AMDase) catalyzes the cofactor‐free asymmetric decarboxylation of prochiral arylmalonic acids and produces the corresponding monoacids with rigorous R selectivity. Alteration of catalytic cysteine residues and of the hydrophobic environment in the active site by protein engineering has previously resulted in the generation of variants with opposite enantioselectivity and