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

Under microwave (MW) irradiation at 150 degree celsius 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.

Automated summary

In this study, 1-substituted 1-ethynyl-2-vinyldi- and tetrahydroisoquinolines were successfully subjected to [3,3]-sigmatropic rearrangement under microwave irradiation at 150 degrees Celsius in toluene, in the presence of nucleophiles (DMAP, triphenylphosphine and tetrahydrothiophene), yielding pyrrolo[2,1-b][3]benzazepines with good yields. The replacement of toluene with acetonitrile directed the rearrangement towards the formation of 7,11b-dihydro-6H-pyrido[2,1-a]isoquinolines.