Photocatalyzed redox-neutral decarboxytative alkylation of heteroaryl methanamines

A redox-neutral decarboxylative coupling reaction of heteroaryl methylamines with NHPI esters derived from aliphatic carboxylic acids has been developed. By employing a copper complex as a photocatalyst with blue LED irradiation, NHPI esters underwent one-electron reduction and heteroaryl methenamine derivatives underwent one-electron oxidation in one photo-redox catalytic cycle to form radical intermediates, respectively, followed by the recombination of these two radicals to form new C-C bonds. The methodology is illustrated by the transformation of different kinds of heteroaromatic compounds as well as primary, secondary and tertiary alkyl carboxylic acids. The reaction can be scaled up and NHPI can be recovered. Also, the reaction can be conducted in a one-pot in situ activation manner.

Automated summary

In this study, a redox-neutral decarboxylative coupling reaction of heteroaryl methylamines with NHPI esters derived from aliphatic carboxylic acids has been developed. By employing a copper complex as a photocatalyst with blue LED irradiation, NHPI esters underwent one-electron reduction and heteroaryl methenamine derivatives underwent one-electron oxidation in one photo-redox catalytic cycle to form radical intermediates, respectively, followed by the recombination of these two radicals to form new C-C bonds. The methodology allows for the transformation of different kinds of heteroaromatic compounds as well as primary, secondary and tertiary alkyl carboxylic acids, and can be scaled up, with NHPI being recoverable and the reaction being conducted in a one-pot in situ activation manner.