Use of the thiophenesulfonyl protecting group in the catalytic, asymmetric synthesis of unprotected β-lactams

Abstract

We have found that the thiophenesulfonyl group is compatible with the catalytic, asymmetric synthesis of β-lactams from acid chlorides and sulfonyl imines in the presence of a silylated cinchona alkaloid and tris(hexamethyl disilazide) lanthanide complex co-catalysts. The thiophenesulfonyl group can be subsequently removed in moderate yields without causing decomposition of the β-lactam or lowering its stereochemical purity.