Catalyst-Controlled Selectivity in the Synthesis of C2-and C3-Sulfonate Esters from Quinoline N-Oxides and Aryl Sulfonyl Chlorides

The first example of the catalyst-controlled selective synthesis of C2- and C3-sulfonate-ester-substituted quinolines was developed by employing LaCl3 and chitosan@CuI catalysts, respectively. This protocol provides an expeditious route to an important class of quinoline derivatives frequently found in many biologically active compounds and features good practicality, high efficiency, and environmental friendliness. In addition, the easily recoverable chitosan@copper catalysts can be recycled five times without significant loss of catalytic performance.