Low-valent Nb(III)-mediated synthesis of 1,1,2-trisubstituted-1H-indenes from aliphatic ketones and aryl-substituted alkynes

A variety of 1,1,2-trisubstituted-1H-indenes are synthesized by the reaction of aliphatic ketones, aryl-substituted alkynes and NbCl3(DME) in 1,2-dichloroethane under reflux conditions.