Cyclopenta[b]indoles. Part 2. Model studies towards the tremorgenic mycotoxins

Abstract

The 7-bromocyclopenta[b]indole 3 has been converted into the hydroxybutenyl derivatives 5 and 6, and the tetrahydrofuranylidene derivative 8 in model studies towards the elaboration of paspalitrem and lolitrem type side chains. In a parallel approach, the cyclopentapyrrole 13 was converted into the fused α-pyrone 16 which acted as a pyrrole-2,3-quinodimethane, and underwent Diels–Alder reaction to give, after loss of carbon dioxide, the cyclopentaindoles 17–21.