Direct Catalytic Asymmetric Conjugate Addition of Saturated and Unsaturated Thioamides

Direct catalytic asymmetric conjugate addition of thiolactams to α,β-unsaturated thioamides was efficiently promoted by a soft Lewis acid/hard Brønsted base cooperative catalyst in a highly stereocontrolled manner. Thioamide functionality was crucial to promote both the efficient enolization of thiolactam pronucleophiles and the subsequent stereoselective conjugate addition to α,β-unsaturated thioamides. Differential manipulation of the two thioamide functionalities of the product highlights the synthetic utility of the present catalytic system.