Iridium-Catalyzed Enantioselective Synthesis of Pyrrole-Annulated Medium-Sized-Ring Compounds.

Enantioselective synthesis of pyrrole-annulated medium-sized-ring compounds by an iridium-catalyzed allylic dearomatization/retro-Mannich/hydrolysis sequence is presented. Various substituted pyrrole-annulated seven- and eight-membered-ring products were obtained under mild reaction conditions with moderate to good yields and excellent enantioselectivity. Additionally, these products contain a scaffold widely distributed in natural products and biologically active compounds. The current method provides a convenient way for accessing such pyrrole-anuulated medium-sized-ring compounds.