Co(III)/Zn(II)-catalyzed dearomatization of indoles and coupling with carbenes from ene-yne ketones via intramolecular cyclopropanation

A straightforward and efficient protocol for dearomatizing indoles is described. The reaction, catalyzed by an inexpensive Co(III)/Zn(II) catalyst, starts from conveniently accessible N-pyrimidinyl indoles and ene-yne ketones. Mild reaction conditions, high diastereoselectivity, a broad substrate scope, reasonable functional group tolerance, and reasonable to remarkable yields were observed.