Enantioselective [4 + 2]-Annulation of Azlactones with Copper-Allenylidenes under Cooperative Catalysis: Synthesis of α-Quaternary α-Acylaminoamides.

The first enantioselective decarboxylative [4 + 2]-annulation of ethynyl benzoxazinanones with azlactones has been developed under cooperative copper and bifunctional tertiary aminourea catalysis. This direct and modular approach combines dipolar copper-allenylidene intermediates with azlactone enolates and allows for the synthesis of α-quaternary α-acylaminoamides as a single diastereomer generally in high yields with good to excellent enantioselectivities (up to 99:1 er).