Assessing the scope of the tandem Michael/intramolecular aldol reaction mediated by secondary amines, thiols and phosphines

The outcome of a tandem Michael/intramolecular aldol reaction which is mediated by secondary amines, thiols and phosphines has been found to be highly substrate dependent, with the best results being obtained for the formation of 5 and 6-membered rings using thiol or thiolate nucleophiles. Amine and phosphine mediated cyclisations were found to be problematic in several cases but were still effective methods for the formation of 5-7 membered rings. (C) 2001 Elsevier Science Ltd. All rights reserved.