Acceptorless cross-dehydrogenative coupling for C(sp3)-H heteroarylation mediated by a heterogeneous GaN/ketone photocatalyst/photosensitizer system

Abstract

Alkanes are naturally abundant chemical building blocks that contain plentiful C(sp³)-H bonds. While inert, the activation of C(sp³)-H via hydrogen atom abstraction (HAT) stages an appealing approach to generate alkyl radicals. However, prevailing shortcomings include the excessive use of oxidants and alkanes that impede scope. We herein show the use of gallium nitride (GaN) as a non-toxic, recyclable, heterogeneous photocatalyst to enable alkyl C(sp³)-H in conjunction with the catalytic use of simple photosensitizer, benzophenone, to promote the desired alkyl radical generation. The dual photocatalytic cycle enables cross-dehydrogenative Minisci alkylation under mild and chemical oxidant-free conditions.