Copper-catalyzed three-component reaction to synthesize polysubstituted imidazo[1,2-]pyridines.

An efficient three-component one-pot and operationally simple cascade of 2-aminopyridines with sulfonyl azides and terminal ynones is reported, providing a variety of polysubstituted imidazo[1,2-]pyridine derivatives in moderate to excellent yields. In particular, the reaction goes a through CuAAC/ring-cleavage process and forms a highly active intermediate α-acyl--sulfonyl ketenimine with base free.