title: Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions.
abstract: Iodination of carbohydrate-derived 3,6-dihydro-2H-1,2-oxazines of type3using iodine and pyridine in DMF furnished 5-iodo-substituted 1,2-oxazine derivatives4with high efficacy. The alkenyl iodide moiety of 1,2-oxazine derivativessyn-4andanti-4was subsequently exploited for the introduction of new functionalities at the C-5 position by applying palladium-catalyzed carbon-carbon bond-forming reactions such as Sonogashira, Heck, or Suzuki coupling reactions as well as a cyanation reaction. These cross-coupling reactions led to a series of 5-alkynyl-, 5-alkenyl-, 5-aryl- and 5-cyano-substituted 1,2-oxazine derivatives being of considerable interest for further synthetic elaborations. This was exemplarily demonstrated by the hydrogenation ofsyn-21andanti-24and by a click reaction of a 5-alkynyl-substituted precursor.
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, D-14195 Berlin, Germany.
authors.forename: Michal
authors.initials: M
authors.lastname: Medvecký
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, D-14195 Berlin, Germany.
authors.forename: Igor
authors.initials: I
authors.lastname: Linder
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, D-14195 Berlin, Germany.
authors.forename: Luise
authors.initials: L
authors.lastname: Schefzig
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
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, D-14195 Berlin, Germany.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Zimmer
keywords: 1,2-oxazines; amino alcohol; click reaction; cross-coupling reactions; hydrogenation; iodination