A simple and convenient strategy for the oxidation of C(sp3)–H bonds based on γ-valerolactone

Abstract

The aerobic oxidation of C(sp³)–H bonds is an important issue in organic synthesis, and hydrogen atom transfer (HAT) is an effective process to initiate the oxidation reaction. Here, we demonstrate an innovative strategy for the oxidation of C(sp³)–H bonds based on γ-valerolactone, which can be produced from biomass. This reaction system promotes the aerobic oxidation of various benzylic and allylic C(sp³)–H bonds and alcohols. Excellent chemoselectivity for 1-isochromanone was achieved with the assistance of Ni₂Al-layered double hydroxide by increasing the difference in bond dissociation energy between the 1- and 4-C–H bonds of isochroman. The excellent application potential of the reaction system has been demonstrated via the synthesis of pharmaceutical molecules, modification of steroidal substrates, scaled-up oxidation experiments, and the ready availability of γ-valerolactone from biomass. This work also reports on a new carbon-centered radical for the activation of C(sp³)–H bonds.