Acyl radicals generated from aldehydes with NHPI as electrocatalyst: aldehydes and alcohols as carbon-centered radical precursors

Abstract

In this work, we describe how N-hydroxyphthalimide (NHPI) promotes hydrogen atom transfer from aldehydes under electrocatalytic chemical conditions. This involves the generation of phthalimide-N-oxyl (PINO), which abstracts an acyl hydrogen to produce acyl radicals from aldehydes. These acyl radicals then react with oximes or another PINO radical to form redox-active esters (RAEs). Additionally, we detail a Giese-type reaction with electron-deficient alkenes via electrochemical reduction of the generated RAE derivatives. This process produces sp³-carbon centered radicals from aldehydes. We also extend this method to aliphatic alcohols, involving a multi-step electrochemical process to form carbon-centered radicals from readily available alcohols.