Peroxydisulfate‐Mediated Transition‐Metal‐Free Oxidative C(sp3)−H Bond Lactonization

Abstract An inexpensive, powerful, and eco‐friendly method for transition‐metal‐free oxidative C(sp 3 )−H bond lactonization was developed using sodium peroxydisulfate as the sole oxidant. The cyclization of 2‐alkylbenzoic acids containing a primary, secondary or tertiary carbon at the benzylic position proceeded smoothly, affording a variety of lactone derivatives. Furthermore, various functional groups such as halogen, cyano, nitro and hydroxy groups were tolerated under the reaction conditions.