Simple and versatile catalytic system for N-alkylation of sulfonamides with various alcohols.

A simple and versatile catalytic system for N-alkylation of sulfonamides with various alcohols based on a catalytic hydrogen transfer reaction has been developed under a low catalyst loading of Cp*IrCl(2) (0.050-1.5 mol %) in the presence of t-BuOK. A variety of N-alkylated sulfonamides were prepared in good to excellent yields. Mechanistic investigations revealed that the key catalytic species in the present system is a sulfonylimido-bridged unsaturated diiridium complex [(Cp*Ir)(2)(mu-NTs)(2)].