OPTICALLY-ACTIVE BUILDING-BLOCKS FROM THE SPAC REACTION - A COMPLETELY ASYMMETRIC-SYNTHESIS OF (4S-CIS)-5-(CYCLOHEXYLMETHYL)-4-HYDROXY-2-PYRROLIDINONE, A STATINE ANALOG

Factors that govern chemical and optical yields of methyl gamma-hydroxy-alpha,beta-unsaturated esters 1 formed in reactions of optically active sulfinylacetates 2 with aldehydes (the ''SPAC'' reaction) are defined. Racemic samples of these chirons (1) can be resolved via acylations mediated by crude preparations of the lipase Pseudomonas K-10 in organic solvents. Combinations of asymmetric SPAC reactions with these biocatalytic resolutions provide routes to highly optically active esters 1 in good yields. This methodology is applied in a completely asymmetric synthesis of (4S-cis)-5-(cyclohexylmethyl)-4-hydroxy-2-pyrrolidinone (15), a cyclic derivative of (3S,4S)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA).