Reactivity of cyclic sulfamidates towards sulfur-stabilised enolates. Stereocontrolled synthesis of functionalised lactams

Abstract

A structurally representative series of 1,2- and 1,3-cyclic sulfamidates react with enolates derived from methyl α-phenylthioacetate 9b to give 5- and 6-substituted α-phenylthio lactams 20–24. These products provide, via the corresponding sulfoxides, an entry to α,β-unsaturated lactams e.g.12, 27, 29 and their α-phenylthio analogues e.g.26 and 30. With the enantiomerically pure 1,2-cyclic sulfamidates 10, 15 and 17, these reactions all proceed with no detectable loss of stereochemical integrity.