Visible-Light-Promoted Cascade Cyclization of 3-Ethynyl-[1,1′-biphenyl]-2-Carbonitriles with Unsaturated α-Bromocarbonyls

Abstract

A visible-light-promoted cascade cyclization of 3-ethynyl-[1,1'-biphenyl]-2-carbonitriles with unsaturated α-bromocarbonyls for the synthesis of tetrahydrobenzo[<i>mn</i>]cyclopenta[<i>b</i>]acridines is described. Three C(sp³)-C(sp²) bonds, one C(sp²)-N bond, and three cycles can be formed in a single reaction through the addition of a C-centered radical to the carbon-carbon triple bond and three radical cyclizations. This reaction features mild conditions, wide substrate scope, and high bond-forming efficiency.