Catalyst-driven scaffold diversity : selective synthesis of spirocycles, carbazoles and quinolines from indolyl ynones

Medicinally relevant spirocyclic indolenines, carbazoles and quinolines can each be directly synthesised selectively from common indolyl ynone starting materials by catalyst variation. The high yielding, divergent reactions all proceed via an initial dearomatising spirocyclisation reaction to generate an intermediate vinyl metal species which then rearranges selectively by careful choice of catalyst and reaction conditions.