Synthesis of Enol Ethers by Coupling Reaction of Alkenyl Halides with Alcohols

Abstract

Herein, we report a new methodology for the synthesis of alkyl enol ethers via the coupling of alkenyl bromides and alkoxy radicals under blue LED irradiation. N,N-Dimethyl formamide di-tert-butyl acetal serves as a precursor to tert-butoxy alkoxy radicals. The generated tert-butoxy alkoxy radicals function as hydrogen atom transfer (HAT) agents, enabling the formation of structurally diverse alkoxy radicals from a wide range of alcohols. Utilizing these alkoxy radicals in combination with alkenyl bromides allows the efficient synthesis of a variety of enol ethers in up to 80% yield, and the reaction exhibits good scalability. This strategy provides a mild and versatile platform for enol ether synthesis and is expected to facilitate broader application of alkoxy radical chemistry in organic synthesis.