Enantioselective construction of [6,5,6]-carbocyclic systems by organo/metal-catalyzed sequential reactions.

An efficient strategy for the enantioselective construction of [6,5,6]-carbocyclic compounds has been established via one-pot reaction of (E)-4-(2-ethynylphenyl)but-3-en-2-ones with maleimide sequentially catalyzed by cinchona alkaloid-based primary amine and gold complex (Ph3PAuNTf2). This methodology provided a facile approach to access the [6,5,6]-tricyclic skeleton in fairly good yield and with perfect enantioselectivities (98% to >99% ee).