Synthesis of mycarose and epi-axenose from non-carbohydrate precursors

✍ Scribed by William R. Roush; Susannah M. Hagadorn

• Book ID: 102991056
• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 644 KB
• Volume: 136
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(85)85195-8

✦ Synopsis

A six-step synthesis of racemic mycarose from allylacetylene is described. Key transformations include the &red-selective epoxidation of (E)-4-methyl-1,4heptadiend-ol and the a-opening of xylo-4,5-epoxy-4-methylhept-l-en-6-01 (7), which was accomplished via a neighboring group-assisted reaction of xylo-4,5epoxy-4-methyl-6-(N-phenylcarbamoyloxy)hept-l-ene (12). The latter conversion proceeded with lower selectivity (3:l) than observed with disubstituted epoxyurethanes because of the greater tendency of trisubstituted epoxides to undergo substitutions with S,l character at the tertiary center. Methanolysis of rib04methylhept-1-ene-4,5,6-trio1 5,6-carbonate, obtained from 12 in up to 61% yield, afforded ribo-4-methylhept-1-ene-4.5,6-triol, which was converted into mycarose by ozonolysis. Similarly, ozonolysis of fyxo-4-methylhept-1-ene-4,5,6triol, which was prepared (64%) by hydrolysis of 7, afforded racemic 3-epi-axenose.