title: An Expedient Route for the Stereoselective Construction of Bridged Polyheterocyclic Ring Systems Using the Tandem "Pincer" Diels-Alder Reaction.
abstract: The tandem "pincer" Diels-Alder reaction, consisting of two consecutive [4 + 2] cycloadditions between two dienes and an acetylenic bis-dienophile, has been applied toward the rapid construction of bridged polyoxacyclic ring systems when furan derivatives are used as the diene components. The study has demonstrated the stereoselectivity (exo-exo adduct), the chemoselectivity ("pincer" vs "domino"), as well as the regioselectivity of the reaction. The reaction has been successfully applied to a variety of 2-substituted furans and tethered bis-furans in combination with monoactivated and diactivated dienophiles. The synthesis of unsymmetrical cycloadducts starting from the aza- and oxanorbornadiene-type intermediate has also been realized.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Lautens
authors.forename: Eric
authors.initials: E
authors.lastname: Fillion