Lipase-catalyzed asymmetric synthesis of 6-(3-chloro-2-hydroxypropyl)-1,3-dioxin-4-ones and their conversion to chiral 5,6-epoxyhexanoates
摘要:
Highly enantioselective syntheses of (R)- and (S)-6-(3-chloro-2-hydroxypropyl)-1,3-dioxin-4-ones by means of lipase-catalyzed kinetic resolutions are described. Chiral dioxinones thus obtained have been converted to optically active 5,6-epoxyhexanoates, which are important precursors for a series of biologically active compounds.
Large-Scale Synthesis of New Pyranoid Building Blocks Based on Aldolase-Catalysed Carbon-Carbon Bond Formation
作者:Michael Wolberg、Ben H. N. Dassen、Martin Schürmann、Stefan Jennewein、Marcel G. Wubbolts、Hans E. Schoemaker、Daniel Mink
DOI:10.1002/adsc.200800224
日期:2008.8.4
A newlarge-scale approach to the synthetically versatile chloromethyl-substituted, α,β-unsaturated δ-lactone 3 is described. The synthesis is based on a biocatalytic process performed on an industrial scale. Conjugate addition of C-, N-, O-, and S-nucleophiles to lactone 3 affords a variety of newpyranoidbuildingblocks in a highly diastereoselective manner. The operational simplicity of the whole
The asymmetric synthesis of an α,β-unsaturated δ-lactone equivalent 8 as a key intermediate towards the total synthesis of a variety of natural products bearing such structural motifs is reported. An enzymatic approach was applied to provide both enantiomers of compound 8 using recLBADH (ee > 99%) and baker's yeast (ee = 94%), respectively. The utility of the intermediate was demonstrated by the total synthesis of the non-natural enantiomers of argentilactone [(S)-1] and goniothalamin [(S)-2].
A stereoselective chemoenzymatic synthesis of all fourstereoisomers of tert-butyl 6-chloro-3,5-dihydroxy-hexanoate (6a) is presented. The key step of the sequence is a highly regio- and enantioselective single-site reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (1a) by two enantiocomplementary biocatalysts. Alcohol dehydrogenase from Lactobacillus brevis (recLBADH) afforded a 72% yield of enantiopure
Highly enantioselective syntheses of (R)- and (S)-6-(3-chloro-2-hydroxypropyl)-1,3-dioxin-4-ones by means of lipase-catalyzed kinetic resolutions are described. Chiral dioxinones thus obtained have been converted to optically active 5,6-epoxyhexanoates, which are important precursors for a series of biologically active compounds.