Alcohols as Alkylating Agents: Photoredox-Catalyzed Conjugate Alkylation via In Situ Deoxygenation

The rapid exploration of sp(3)-enriched chemical space is facilitated by fragment-coupling technologies that utilize simple and abundant alkyl precursors, among which alcohols are a highly desirable, commercially accessible, and synthetically versatile class of substrate. Herein, we describe an operationally convenient, N-heterocyclic carbene (NHC)-mediated deoxygenative Giese-type addition of alcohol-derived alkyl radicals to electron-deficient alkenes under mild photocatalytic conditions. The fragment coupling accommodates a broad range of primary, secondary, and tertiary alcohol partners, as well as structurally varied Michael acceptors containing traditionally reactive sites, such as electrophilic or oxidizable moieties. We demonstrate the late-stage diversification of densely functionalized molecular architectures, including drugs and biomolecules, and we further telescope our protocol with metallaphotoredox cross-coupling for step-economic access to sp(3)-rich complexity.

Automated summary

In this paper, a convenient catalytic method for the coupling of alcohols with alkenes under mild photocatalytic conditions using N-heterocyclic carbene (NHC)-mediated deoxygenative Giese-type addition is described. This method is applicable to a wide range of alcohol compounds and allows for late-stage diversification reactions, showing significant potential for various applications.