COMBINATION OF BORANE-DIMETHYL SULFIDE COMPLEX WITH CATALYTIC SODIUM TETRAHYDROBORATE AS A SELECTIVE REDUCING AGENT FOR α-HYDROXY ESTERS. VERSATILE CHIRAL BUILDING BLOCK FROM (S)-(−)-MALIC ACID

Borane-dimethyl sulfide complex has proven to be an efficient and selective reducing agent in the presence of catalytic sodium tetrahydroborate for α-hydroxy esters as exemplified in the reduction of dimethyl (S)-(−)-malate, providing the versatile chiral building block of four-carbon backbone.