The continuous-flow electrosynthesis of 4-(sulfonylmethyl)isoquinoline-1,3(2: H,4 H)-diones from N -alkyl- N -methacryloyl benzamides under metal-free and oxidant-free conditions

An efficient and green electrochemical continuous-flow approach has been developed for the synthesis of 4-(sulfonylmethyl)isoquinoline-1,3(2H,4H)-diones through the sulfonylation of alkenes with sulfonylhydrazides. The reaction proceeds in a continuous-flow electrolytic cell under metal-free and oxidant-free conditions. A series of activated alkenes were suitable for this system, and the corresponding products were obtained in moderate to good yields. Moreover, reaction scale-up was smoothly achieved using the electrochemical continuous-flow system without changing the reaction conditions.