The Facile and Efficient Three-Component One-Pot Mannich-Type Reaction of Indoles Catalyzed by In(OTf)3 Under Microwave Irradiations

Indium triflate catalysed the three-component one-pot reaction of indole 1 with a heteroimine generated in situ under microwave irradiations and afforded predominately secondary indolyl amines 4 in excellent yields as well as bisindolyl methane 5 in poor yields. The catalyst indium triflate can be recovered after the reaction and reused in the subsequent experiments.