Facile syntheses of valiolamine and its diastereomers from (-)-quinic acid.1 nucleophilic substitution reactions of 5-(hydroxymethyl)cyclohexane-1,2,3,4,5-pentol

Tony K.M. Shing, Leong H. Wan

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40 Citations (Scopus)

Abstract

Valiolamine (1), 1-epi-valiolamine (2), 2-epi-valiolamine (3), (1R,2R)-valiolamine (4), and 2-amino regioisomer 17 have been prepared from (-)-quinic acid (6) in 14 (8.4% overall yield), 13 (9.0%), 15 (4.3%), 17 steps (2.5%), and 12 steps (13%), respectively. Charged nucleophilic ring-openings of cyclic sulfate (1R,2S,3S,4S,5S)-4,5-di-O-acetyl-3-O-benzyl-5-(benzyloxymethyl)-1,2-O,O- sulfonylcyclohexane-1,2,3,4,5-pentol (11) occurred regioselectively at C-2, whereas the corresponding ring-openings of its (1S,2R)-diastereomer 34 proceeded preponderantly at C-1. (1R,2S,3R,4S,5S)-2,4,5-Tri-O-acetyl-3-O-benzyl-5-((benzyloxy)methyl)-1-O- (trifluoromethanesulfonyl)cyclohexane-1,2,3,4,5-pentol (24) underwent novel internal displacement spontaneously to form (1S,2S,3R,4S,5S)-1,2,4-tri-O-acetyl-3-O-benzyl-5-((benzyloxy)methyl)cyclohexane- 1,2,3,4,5-pentol (25), whereas its 2-epimer was inert under the same conditions. Ruthenium-catalyzed dihydroxylation of alkene, (3R,4S,5S)-4,5-O-acetyl-3-O-benzyl-5-((benzyloxy)methyl)-1-cyclohexene-3,4,5- triol (31), gave the desired β-1,2-diol 32 in higher yield and stereoselectivity than the osmium tetraoxide protocol. The regioselectivity of charged nucleophilic ring-openings of cyclic sulfates 11, 34, and 38 is discussed.

Original languageEnglish
Pages (from-to)8468-8479
Number of pages12
JournalJournal of Organic Chemistry
Volume61
Issue number24
Publication statusPublished - 1996 Nov 29

ASJC Scopus subject areas

  • Organic Chemistry

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