Synthesis 2011(1): 109-118  
DOI: 10.1055/s-0030-1258326
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

β-Alkoxy-γ-amino Aldehydes by Internal Redox Ring Cleavages of Carbohydrate-Derived Enantiopure 1,2-Oxazines and Preparation of Heterocycles with Aminopolyol Side Chain

Ahmed Al-Harrasia,b, Léa Bouchéa, Reinhold Zimmera, Hans-Ulrich Reissig*a
a Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
Fax: +49(30)83855367; e-Mail: hans.reissig@chemie.fu-berlin.de;
b University of Nizwa, College of Arts and Sciences, Department of Biological Sciences and Chemistry, P.O Box 33, Postal Code 616, Birkat Al Mauz, Nizwa, Sultanate of Oman
Further Information

Publication History

Received 7 September 2010
Publication Date:
15 November 2010 (online)

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Abstract

N-Methylation of syn- or anti-configured 3,6-dihydro-2H-1,2-oxazines and subsequent treatment with triethylamine smoothly provided enantiopure α,β-unsaturated β-alkoxy-γ-amino aldehydes bearing different protected diol, triol, or tetrol side chains in good to excellent yields. The N-O bond cleavage occurs under mild conditions and involves an internal redox process. The method is also applicable to tetrahydro-2H-1,2-oxazines, which either lead to 4-amino ketose or aldose derivatives (d-sorbose or d-idose configuration). The equivalency of the generated β-alkoxyenal moiety with 1,3-dicarbonyl compounds could be demonstrated by condensation reactions with hydrazine or 2-aminoimidazole derivatives providing a series of new pyrazole or imidazo[1,2-a]pyrimidine derivatives with stereodefined and protected aminopolyol side chains.