title: Galloyl-Derived Orthoquinones as Reactive Partners in Nucleophilic Additions and Diels-Alder Dimerizations: A Novel Route to the Dehydrodigalloyl Linker Unit of Agrimoniin-Type Ellagitannins.
abstract: Orthochloranil-mediated oxidation of galloyl monoethers furnishes the derived orthoquinones in excellent yield. These reactive electrophiles participate in a variety of nucleophilic addition reactions with heteroatomic and carbanionic partners. In addition, Lewis acid-mediated dimerization of the orthoquinones provides an efficient route to dehydrodigalloyl-type diaryl ether units characteristic of several ellagitannin natural products. The implications for ellagitannin biosynthesis and gallotannin-protein covalent attachment are discussed.
authors.affiliation: Department of Chemistry and Pesticide Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802.
authors.forename: Ken S.
authors.initials: KS
authors.lastname: Feldman
authors.forename: Stéphane
authors.initials: S
authors.lastname: Quideau
authors.forename: Heidi M.
authors.initials: HM
authors.lastname: Appel