- Synthesis of zymosterol, fecosterol, and related biosynthetic sterol intermediates
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The first syntheses of sterol biosynthetic intermediates zymosterol(4), 4,4-dimethylzymosterol(5), cholesta-8,14,24-trien-3β-ol(6), the 4,4-dimethyl analogue 7, and fecosterol (8) are described in detail. Multigram quantities of key intermediates 16 and 17 were efficiently prepared from known enones 20 and 21 (eight steps, 35% overall yield). Novel entry into Δ8-sterols was achieved through regiospecific hydroboration/deoxygenation of the 8,14-diene systems. Sterols containing Δ24- or Δ(24(28))-olefins were obtained from C24-hydroxy intermediates either via dehydration using bis[α,α-bis(trifluoromethyl)benzenemethanolato]diphenylsulfur in CH2Cl2 or via Swern oxidation/Wittig olefination, respectively. In this way, 16 and 17 were converted to the desired Δ8,24-, Δ8,14,24-, and Δ(8,24(28))-sterols with high regiocontrol.
- Dolle,Schmidt,Erhard,Kruse
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p. 278 - 284
(2007/10/02)
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- Synthesis of Zymosterol: Salient Intermediate of Fungal and Mammalian Sterol Biosynthesis
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A useful strategy for the construction of sterol biosynthetic intermediates possessing Δ8-unsaturation is described and exemplified by the synthesis of zymosterol (1) and 24,25-dihydrozymosterol (2).
- Dolle, Roland E.,Schmidt, Stanley J.,Kruse, Lawrence I.
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