Reductive Dechlorination of Aryl Chlorides Using Hantzsch Ester.

Herein, we report a transition-metal-free reductive dechlorination of aryl and alkyl chlorides using Hantzsch ester as the sole reductant. Operating under 365 nm UV irradiation or at 100 °C temperature, this method represents a significant simplification without the need for additional catalysts or inert protection. It exhibits excellent chemoselectivity, with reduction-sensitive functional groups, such as esters, aldehydes, and ketones, left completely intact. Mechanistic studies and DFT calculations reveal divergent mechanisms: a concerted SNAr pathway under thermal conditions while a single-electron transfer (SET) pathway under photochemical conditions.