γ-Alkylation of Alcohols Enabled by Visible-Light Induced 1,6-Hydrogen Atom Transfer

Org Lett. 2019 Aug 2;21(15):6107-6111. doi: 10.1021/acs.orglett.9b02255. Epub 2019 Jul 24.

Abstract

Site-selective remote alkylation of alcohol is attractive but challenging in organic synthesis. Herein, we report a novel visible-light mediated γ-alkylation of alcohol derivatives via the formation of Csp3-Csp3 bond through Csp3-H bond functionalization under mild conditions. The use of sulfamate esters enables the directed, otherwise rare 1,6-HAT to generate γ-selective C-centered radical, which is complementary to δ-selective 1,5-HAT of alcohols. This redox-neutral protocol provides a general and operationally simple method to access γ-alkylated alcohols.