Ferric Chloride-Mediated Transacylation of -Acylsulfonamides.

Transacylation of -acylsulfonamides, which replaces the -acyl group with a new one, is a challenging and underdeveloped fundamental transformation. Herein, a general method for transacylation of -acylsulfonamides is presented. The transformation is enabled by coincident catalytic reactivities of FeCl for nonhydrolytic deacylation of -acylsulfonamides and subsequent acylation of the resultant sulfonamides and can be conducted either stepwise or in a one-pot manner. GaCl and RuCl·HO are similarly effective for the reaction. This method is mild, efficient, and operationally simple. A variety of functional groups such as halogeno, keto, nitro, cyano, ether, and ester are well tolerated, providing the transacylation products in good to excellent yields.