title: Constructing the Architecturally Distinctive ABD-Tricycle of Phomactin A through an IntramolecularOxa-[3 + 3] Annulation Strategy.
abstract: Our efforts in constructing the ABD-ring of phomactin A through an intramolecularoxa-[3 + 3] annulation strategy is described. This struggle entailed finding a practical and efficient preparation of annulation precursor, and a realization of the unexpected competing regioisomeric pathway. The success entailed accessing the A-ring through Diels-Alder cycloaddition of Rawal's diene. Furthermore, the discovery that the regioisomers from the annulation existed as atropisomers with respect to the D-ring olefin and that they could be equilibrated to the desired ABD-tricycle, allowing large quantities of tricycle to be accessed.
authors.affiliation: Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, Madison, WI 53705 USA.
authors.forename: Grant S
authors.initials: GS
authors.lastname: Buchanan
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Cole
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Tang
authors.forename: Ling-Feng
authors.initials: LF
authors.lastname: You
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hsung
keywords: ABD-tricycle; Phomactin A; Rawal’s Diels-Alder Cycloaddition; atropisomers; intramolecular oxa-[3 + 3] annulation