Direct Catalytic Asymmetric Vinylogous Conjugate Addition of Unsaturated Butyrolactones to α,β‐Unsaturated Thioamides

Soft Lewis acid/Brønsted base cooperative catalysts have enabled direct catalytic asymmetric vinylogous conjugate addition of α,β- and β,γ-unsaturated butyrolactones to α,β-unsaturated thioamides with perfect atom economy. When using α-angelica lactone and its derivatives as pronucleophiles, as little as 0.5 mol% catalyst loading was sufficient to complete the reaction necessary to construct consecutive tri- and tetrasubstituted stereogenic centers in a highly diastereo- and enantioselective fashion.