A highly efficient and enantioselective (>99.5% ee) synthesis of the t
itle compound has been accomplished. Key steps include (1) epoxidation
of unsaturated ketone 7 in the presence of a polyamino acid to afford
compound 8 in >95% ee, (2) regioselective Baeyer-Villiger rearrangeme
nt of epoxy ketone 8 to afford glycidic ester 9, and (3) regioselectiv
e (35:1) opening of lithium glycidate 13 at C-3 with methyl 3-mercapto
propionate. The approach is economical, and all transformations procee
d in high yield and are amenable to large-scale preparation.