Mild and efficient indium metal catalyzed synthesis of sulfonamides and sulfonic esters

A facile and efficient method for synthesizing sulfonamides was developed using a catalytic amount of indium metal. A wide range of sulfonamides were synthesized in excellent yields using the new process. The method showed a generality for substrates including less nucleophilic and sterically hindered anilines, and it is also applicable for preparing sulfonic esters from sulfonyl chlorides and alcohols.