Catalytic asymmetric conjugate addition of simple alkyl thiols to alpha,beta-unsaturated N-acylated oxazolidin-2-ones with bifunctional catalysts.

Abstract

In this communication, we describe an unprecedented highly enantioselective catalytic conjugate addition of simple alkyl thiols to alpha,beta-unsaturated N-acylated oxazolidin-2-ones catalyzed by acid-base bifunctional catalysis. This reaction provides a useful catalytic method for the synthesis of optically active chiral sulfur compounds that are otherwise difficult to prepare by asymmetric catalysis. The successful development of this reaction resulted from a discovery that, upon proper modification, a cinchona alkaloid bearing a thiourea functionality at 6' position can afford highly efficient catalysis for asymmetric conjugate additions.