Reusable ionic liquid-catalyzed oxidative esterification of carboxylic acids with benzylic hydrocarbons via benzylic Csp3–H bond activation under metal-free conditions

A metal-free protocol for the direct oxidative esterification of the Csp3–H bond in benzylic hydrocarbons with carboxylic acids using heterocyclic ionic liquid as catalyst has been reported. The catalyst 1-butylpyridinium iodide could be easily recycled and reused for at least four cycles without obvious loss of catalytic activity.