Enantioselective gold catalyzed dearomative [2+2]-cycloaddition between indoles and allenamides

The highly enantioselective synthesis of densely functionalized 2,3-indoline-cyclobutanes by means of chiral gold catalysis is presented. Intermolecular formal [2+2]-cycloaddition reactions between substituted indoles and allenamides enabled direct access to methylenecyclo- butane-fused indolines, featuring two consecutive quaternary stereo- genic centers with excellent stereochemical control (dr 4 20:1, ee up to 99%)