Nickel Photocatalyzed Reductive 1,4-Dicarbofunctionalization of 1,3-Enynes with N-Methylamines and Organohalides Enabled by Site-Selective C(sp3)-H Functionalization.

Abstract

A cooperative nickel and photoredox reductive catalysis for 1,4-dicarbofunctionalization of 1,3-enynes with tertiary N-methylamines and organohalides to produce tetrasubstituted allenes is presented. This method enables the generation of the aminoalkyl C(sp3)-centered radicals by site selective cleavage of the N-methyl C(sp3)-H bonds in tertiary N-methylamines and is extended to alkyl bromides as the electrophilic terminating regents. Mechanistic studies indicate that the reaction involves a radical process and a Ni0/NiI/NiIII catalytic cycle.