Enantioselective Synthesis of 2,2,3-Trisubstituted Indolines via Bimetallic Relay Catalysis of α-Diazoketones with Enones

An efficient asymmetric intramolecular trapping of ammonium ylides of alpha-diazoketones with enones to synthesize indoline derivatives was realized. A Rh(II)/chiral N,N'-dioxide-Sc(III) complex bimetallic relay catalytic system was established. A series of optically active 2,2,3-trisubstituted indolines were obtained in high yields (up to 99%), good enantioselectivities (up to 99% ee), and excellent diastereoselectivities (up to >19:1 dr) under mild reaction conditions.