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DOI: 10.1055/s-1995-5161
Synthesis and cis-Dihydroxylation of 6H-1,2-Oxazines: Synthesis of Dihydroxyprolinols
Publication History
Publication Date:
31 December 2000 (online)
An efficient synthesis of 6H-1,2-oxazines 5a-f starting from α-halogen oximes 2a-f and β-bromo enol ether 1 is described. Compounds 5a-d were cis-dihydroxylated with KMnO4 and compound 5e with the NaIO4/RuCl3 reagent, respectively, to give the diastereomerically pure functionalized 1,2-oxazines 7a-e after protection. Intermediate 7a could be transformed into cis-dihydroxylated proline derivatives 8α, 8β which were converted to dihydroxyprolinols 10α and 10β or to the N-benzylated compounds 9α and 9β. This route constitutes a formal total synthesis of swainsonine 11 since 9β is a known intermediate in a published synthesis of this natural mannosidase inhibitor.
6H-1,2-Oxazines - cis-Dihydroxylation - Pyrrolidine Derivatives - Hetero-Diels-Alder Reaction - Swainsonine