Synergistic Activation of Amides and Hydrocarbons for Direct C(sp(3))-H Acylation Enabled by Metallaphotoredox Catalysis

Abstract

The utilizations of omnipresent, thermodynamically stable amides and aliphatic C(sp(3))-H bonds for various functionalizations are ongoing challenges in catalysis. In particular, the direct coupling between the two functional groups has not been realized. Here, we report the synergistic activation of the two challenging bonds, the amide C-N and unactivated aliphatic C(sp(3))-H, via metallaphotoredox catalysis to directly acylate aliphatic C-H bonds utilizing amides as stable and readily accessible acyl surrogates. N-acylsuccinimides served as efficient acyl reagents for the streamlined synthesis of synthetically useful ketones from simple C(sp(3))-H substrates. Detailed mechanistic investigations using both computational and experimental mechanistic studies were performed to construct a detailed and complete catalytic cycle. The origin of the superior reactivity of the N-acylsuccinimides over other more reactive acyl sources such as acyl chlorides was found to be an uncommon reaction pathway which commences with C-H activation prior to oxidative addition of the acyl substrate.