title: Benzofulvenes in Trienamine Catalysis: Stereoselective Spiroindene Synthesis.
abstract: The asymmetric formation of spiroindenes containing up to four contiguous stereocenters from the reaction of benzofulvenes with 2,4-dienals through trienamine catalysis is described. The benzofulvene core was found to be an excellent starting point for the synthesis of interesting spiroindenes through a formal cycloaddition pathway. The reaction was mediated by a diphenylprolinol silyl ether catalyst, and a diverse array of spiroindenes were obtained in high yields with excellent stereoselectivity. An attractive feature of the developed system is the possibility to diversify the product scaffold significantly by further manipulation of the chiral spiroindenes. Thus, three intramolecular ring-closing reactions following the organocatalytic step resulted in highly complex polycyclic systems.
authors.affiliation: Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Bjarke S
authors.initials: BS
authors.lastname: Donslund
authors.affiliation: Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Rune Pagh
authors.initials: RP
authors.lastname: Nielsen
authors.affiliation: Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Sofie M N
authors.initials: SM
authors.lastname: Mønsted
authors.affiliation: Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark. kaj@chem.au.dk.
authors.forename: Karl Anker
authors.initials: KA
authors.lastname: Jørgensen
keywords: asymmetric catalysis; benzofulvenes; spiro compounds; spiroindenes; trienamine catalysis