Asymmetric catalytic synthesis 2,2,3-trisubstituted indolines is interesting and challenging. we have developed an efficient asymmetric bimetallic relay catalysis to synthesize 2,2,3-trisubsituted indolines via intramolecular trapping of ammonium ylides with enones. In previous report, Rh(II)/chiral phosphoric acid combination was used to the reaction between α-diazoesters and enones for this purpose, but the enantioselectivity is poor. And the use of a Lewis acid cocatalyst rather than a Bronsted acid resulted in no reaction. To address the enantioselective control in this cascade reaction, we utilized α-diazoketone instead of α-diazoester to increase the reaction efficiency and reduce the steric hindrance. By the use of Rh(II)/chiral N,N′-dioxide-Sc(III) complex bimetallic relay catalytic system, a wide range of optically active 2,2,3-trisubstituted indolines was obtained in high yields (up to 99%), good enantioselectivities (up to 99% ee), and excellent diastereoselectivities (up to &gt;19:1) under mild reaction conditions.

Enantioselective synthesis of 2,2,3-trisubstituted indolines via bimetallic relay catalysis of α-diazoketones with enones

2019 Fall National Meeting

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