Synlett 1999; 1999(10): 1654-1656
DOI: 10.1055/s-1999-2892
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Synthesis of Bis(enolnonaflates) and their 4-exo-trig-Cyclizations by Intramolecular Heck Reactions

Stefan Bräse*
  • *Institut für Organische Chemie der Technischen Hochschule, Professor-Pirlet-Straße, D-52074 Aachen, Germany; Fax + (49) (0)2 41/8 88 81 27; E-mail: Braese@oc.RWTH-Aachen.de
Further Information

Publication History

Publication Date:
31 December 1999 (online)

Starting from dimedone, novel 1,3-bis(enolnonaflates) (nonafluorobutanesulfonates) have been prepared in four efficient steps. Cyclization of these 1,5-hexadienes under Palladium catalysis proceeded cleanly to give bicyclo[4.2.0]octadienes and bicyclo[4.2.0]octenones, respectively, by an unprecedented 4-exo-trig process. Insertion in one enolsulfonate moiety, intramolecular cyclization and subsequent second insertion after intermolecular reaction with alkenes (acrylates) or alkynes (3,3-dimethylbutyne) led to novel, highly congested hydrocarbons. Application of a chiral catalyst system resulted in modest asymmetric induction to furnish an enantioselective Heck-type desymmetrization reaction product.