title: Diastereoselective [4 + 4]-photocycloaddition reactions of pyran-2-ones: rapid access to functionalized 5-8-5 skeletons.
abstract: Fused bicyclic pyran-2-ones with pendant furan side chains and an oxygenated stereogenic center adjacent to the pyranone ring oxygen were prepared via FeCl(3)-catalyzed Michael addition. Irradiation furnished the corresponding lactone-bridged tricyclic [4 + 4]-cycloadducts with good facial selectivity. Surprisingly, the major isomer resulted from approach of the furan from the same face as the protected alcohol. [reaction: see text]
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2.
authors.forename: Dong
authors.initials: D
authors.lastname: Song
authors.forename: Robert
authors.initials: R
authors.lastname: McDonald
authors.forename: F G
authors.initials: FG
authors.lastname: West