American Chemical Society
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Enantiospecific Syntheses of Valienamine and 2-epi-Valienamine1

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journal contribution
posted on 1999-02-24, 00:00 authored by Tony K. M. Shing, Tin Y. Li, Stanton H.-L. Kok
Cyclic sulfite 10, readily available from (−)-quinic acid (3) in 10 steps, was ring opened regio- and stereospecifically with azide anion to give (1S,2R,3R,4R)-1-azido-3,4-di-O-benzyl-5-(benzyloxymethyl)cyclohex-5-ene-2,3,4-triol (11). Deprotection of 11 afforded, for the first time, 2-epi-valienamine (2), which was isolated as penta-N,O-acetyl-2-epi-valienamine (14). The configuration of the free hydroxy group in 11 was inverted by a two-step sequence to give the blocked valienamine 19 that was deprotected to give valienamine (1), isolated as penta-N,O-acetylvalienamine (21). This approach furnished (+)-valienamine (1) in 16 steps (7% overall yield) and recorded the first synthesis of 2-epi-valienamine (2) in 13 steps (11% overall yield).