Synergistic Copper and Chiral Lewis Base Catalysis for the Asymmetric Synthesis of Pyrrolo[1,2‐a]indoles

Main observation and conclusion The first asymmetric decarboxylative [3+2]‐cycloaddition of ethynyl indoloxazolidones with carboxylic acids has been developed under synergistic catalysis of copper and chiral Lewis base. This protocol provides a direct and modular approach to biologically important pyrrolo[1,2‐a]indoles bearing two vicinal stereogenic centers with excellent diastereo‐ and enantioselectivities (up to >20 : 1 dr and >99% ee). In addition, the utility of this methodology was demonstrated by scaled‐up reaction and several synthetic transformations of the cycloadduct.