Divergent and Nucleophile-Assisted Rearrangement in the Construction of Pyrrolo[2,1-b][3]benzazepine and Pyrido[2,1-a]isoquinoline Scaffolds

Abstract

Under microwave (MW) irradiation at 150 °C in toluene and in the presence of nucleophiles (DMAP, triphenylphosphine and tetrahydrothiophene) 1-substituted 1-ethynyl-2-vinyldi- and tetrahydroisoquinolines undergo [3,3]-sigmatropic rearrangement providing pyrrolo[2,1-b][3]benzazepines in good yields. The replacement of toluene with acetonitrile directs the rearrangement towards the formation of 7,11b-dihydro-6H-pyrido[2,1-a]isoquinolines.

Keywords: microwave irradiation; pyrido[2,1-a]isoquinolines; pyrrolo[2,1-a]isoquinolines; pyrrolo[2,1-b][3]benzazepines; sigmatropic rearrangement.