García-Granados Andrés, Gutiérrez María C, Martínez Antonio, Rivas Francisco
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada, 18071-Granada, Spain.
J Org Chem. 2005 Jan 7;70(1):338-41. doi: 10.1021/jo048783k.
Two new 7-epi-eudesmane derivatives, together with two new germacrane compounds, have been isolated from the microbial-transformation of a (1alpha,10beta),(4beta,5alpha)-diepoxygermacrane using the hydroxylating fungi Rhizopus nigricans. The rearranged skeleton and the stereochemistry of the chiral centers have been determined by means of their spectral data, and the absolute configuration has been confirmed by single-crystal X-ray analyses. A possible mechanism based on an enzyme-catalyzed isomerization to a 1alpha-hydroxy-(4beta,5alpha)-epoxygermacr-9(E)-ene intermediate and a subsequent cyclization process is proposed in order to explain the formation of the 7-epi-eudesmane compounds.
利用产黄青霉进行羟化反应，从(1α,10β),(4β,5α)-二环氧吉马烷的微生物转化产物中分离出两种新的7-表桉叶烷衍生物以及两种新的吉马烷类化合物。通过光谱数据确定了重排骨架和手性中心的立体化学结构，并通过单晶X射线分析确证了绝对构型。为解释7-表桉叶烷类化合物的形成过程，提出了一种可能的机制，即酶催化异构化为1α-羟基-(4β,5α)-环氧吉马-9(E)-烯中间体，随后发生环化反应。
