Improved Synthesis of the C8-C23 Segment of Aplysiatoxins via Asymmetric Dihydroxylation of the Chiral Homoallylic Alcohol.
Important intermediate 2 of the segment (3) possessing four sequential asymmetric centers (C9-C12) of aplysiatoxins was synthesized via dihydroxylation of 5 in only 7 steps from methyl (S)-3-hydroxy-2-methylpropionate. Another promising compound (10a) was also synthesized in only 6 steps via asymmetric dihydroxylation of chiral homoallylic alcohol 4 as the key step.
a Department of Bioscience and Chemistry, Faculty of Agriculture, Hokkaido University.
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Toshima
a Department of Bioscience and Chemistry, Faculty of Agriculture, Hokkaido University.
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Ichihara
aplysiatoxin; asymmetric dihydroxylation; crotylboration; protein kinase C; tumor promoter