title: Synthesis of rigid p-terphenyl-linked carbohydrate mimetics.
abstract: An approach to β-D-2-aminotalose- and β-D-2-aminoidose-configured carbohydrate mimetics bearing a phenyl substituent is described. Unnatural divalent rigid p-terphenyl-linked C-aryl glycosides with 2.0 nm dimension are available using Suzuki cross-couplings. The key compound, a p-bromophenyl-substituted 1,2-oxazine, was prepared by a stereoselective [3 + 3]-cyclization of a D-isoascorbic acid-derived (Z)-nitrone and lithiated TMSE-allene. The Lewis acid-induced rearrangement of this heterocycle provided the corresponding bicyclic 1,2-oxazine derivative that may be regarded as internally protected amino sugar analogue. After subsequent reduction of the carbonyl group, the resulting bicyclic compound was used for Suzuki cross-couplings to form biphenyl aminopyran or p-terphenyl-linked dimers. Hydrogenolysis afforded new unnatural aminosugar mimetics. Zinc in the presence of acid or samarium diiodide were examined for the N-O bond cleavage in order to obtain the rigid p-terphenyl-linked C-glycosyl dimers.
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustraße 3, D-14195 Berlin, Germany.
authors.forename: Maja
authors.initials: M
authors.lastname: Kandziora
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustraße 3, D-14195 Berlin, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Reissig
keywords: 1,2-oxazines; Suzuki cross-coupling; carbohydrate mimetics; hydrogenolysis; multivalent glycosystems; samarium diiodide