Baker’s yeast-mediated enantioselective synthesis of the bisabolane sesquiterpenes (+)-curcuphenol, (+)-xanthorrhizol, (−)-curcuquinone and (+)-curcuhydroquinone
作者:Claudio Fuganti、Stefano Serra
DOI:10.1039/b006141g
日期:——
yields and shows complete enantioselectivity in the formation of the (S)-(+) isomers. Enantiopure 6a–c are versatile chiral building blocks for the synthesis of bisabolane sesquiterpenes. Their usefulness is shown in the preparation of (S)-(+)-curcuphenol, (S)-(+)-xanthorrhizol, (S)-(−)-curcuquinone and (S)-(+)-curcuhydroquinone.
A synthesis of (-)-curcuphenol, (-)-curcuquinone and (-)-curcuhydroquinone from o-valerolactone is described. The key steps include an Evans asymmetric methylation of 5-(benzyloxy)pentanoic acid (5), an oxidative aromatization of enone (11) and a regioselective oxidation of the phenol to o-quinone derivative with bis(trifluoro acetate)iodobenzene.
A diterpene, a sesquiterpene quinone and flavanones from Wyethia helenioides
作者:Ferdinand Bohlmann、Christa Zdero、Harold Robinson、Robert M. King
DOI:10.1016/0031-9422(81)80122-7
日期:1981.1
Abstract The aerial parts of Wyethiahelenioides afforded a new geranyl nerol derivative (a 16-hydroxy-18-oic acid), two isomeric prenylated lavanones and a quinone derived from bisabolene. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.
Heliannuols D and A, which exhibit allelopathic activity, were synthesized enantioselectively via a base-mediated intramolecular cyclisation of a phenolic epoxide for the first time, and the absolute structures were established by total synthesis.