Convenient construction of tetrahydrochromeno[4',3':2,3]indolizino[8,7-]indoles and tetrahydroindolizino[8,7-]indoles one-pot domino reaction.

The functionalized tetrahydrochromeno[4',3':2,3]indolizino[8,7-]indoles were conveniently synthesized in high yields by one-pot domino reaction of tryptamines, alkyl propiolates and 2-aryl-3-nitro-2-chromenes. Under similar conditions, the one-pot reaction of tryptamines, alkyl propiolates and β-nitroalkenes resulted in functionalized tetrahydroindolizino[8,7-]indoles. The reaction mechanism involved sequential generation of β-enamino ester, Michael addition, Pictet-Spengler reaction and annulation process. The reaction showed high atomic economy and met the goals of sustainable chemistry.