title: Cyclofunctionalization and free-radical-based hydrogen-transfer reactions. An iterative reaction sequence applied to the synthesis of the C(7)-C(16) subunit of zincophorin.
abstract: The strategy considered herein features an iodocyclofunctionalization/hydrogen-transfer reaction sequence for the elaboration of propionate motifs. Proceeding with excellent yield and diastereoselectivity, the synthetic sequence proposed gives access to the anti-anti dipropionate motif when the reduction step is performed under the control of the exocyclic effect. The tandem sequence is applied successfully to the synthesis of the C(7)-C(16) subunit of zincophorin, and iteration of the process gives the desired anti-anti-anti-anti polypropionate stereopentad. Modifications of the reaction sequence--including phenylselenocyclofunctionalization, carbonate hydrolysis, and chelation-controlled radical reduction reactions--lead to the formation of the anti-syn dipropionate motif with remarkable diastereocontrol.
authors.affiliation: Institut de recherches cliniques de Montréal, Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7. guindoy@ircm.qc.ca
authors.forename: Y
authors.initials: Y
authors.lastname: Guindon
authors.forename: L
authors.initials: L
authors.lastname: Murtagh
authors.forename: V
authors.initials: V
authors.lastname: Caron
authors.forename: S R
authors.initials: SR
authors.lastname: Landry
authors.forename: G
authors.initials: G
authors.lastname: Jung
authors.forename: M
authors.initials: M
authors.lastname: Bencheqroun
authors.forename: A M
authors.initials: AM
authors.lastname: Faucher
authors.forename: B
authors.initials: B
authors.lastname: Guérin