One-Pot Synthesis of 2,3-Disubstituted Indoles

Significance

A one-pot regioselective synthesis of 2,3-disubstituted indoles from the reaction of 2-iodoacetanilides with terminal alkynes is described. The reaction, proceeding under Pd-catalysis, involves an initial Sonogashira coupling followed by amidopalladation/reductive elimination (first reported by Cacchi) and proceeds under mild conditions in good yields. The scope of the reaction is inextensively defined: only two R¹ electron-withdrawing groups and limited alkynes were tested; however, both electron-donating and -withdrawing groups were effective in the Cacchi process.