Chemo- and regioselective synthesis of C3-sulfonate esters and C4-chlorides of quinolines under metal-free conditions†

Disclosed herein is a novel one-pot synthesis of C3-sulfonate esters and C4-chlorides of quinolines from quinoline N-oxides with sulfonyl chloride. Sulfonyl chlorides were used in two roles, namely sulfonylation and chlorination. Both arenesulfonyl chlorides and aliphatic sulfonyl chlorides were found to be suitable precursors for sulfonation and chlorination reagents. Therefore, a wide variety of C3-sulfonate esters and C4-chlorides of quinolines were afforded under metal-free conditions. This procedure features practicality, high efficiency, environmental friendliness and atomic economy.