title: Stereodivergent de novo synthesis of branched amino sugars by lewis Acid promoted rearrangement of 1,2-oxazines.
abstract: Well concealed: 1,2-oxazines such as 1 rearrange under Lewis acidic conditions to bicyclic products of type 2, which can be incorporated into oligosaccharides as protected amino sugar equivalents. Subsequent reductive steps provide unusual oligosaccharides 3 having C2-branched 4-amino sugar units. Most of the reactions proceed with excellent stereocontrol and allow the synthesis of a collection of stereoisomers.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Pfrengle
authors.forename: Dieter
authors.initials: D
authors.lastname: Lentz
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Reissig