jo048783k_si_002.cif (17.98 kB)
Download fileEnzyme-Catalyzed Rearrangement of a Diepoxy-germacrane Compound into New 7-epi-Eudesmane Derivatives
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posted on 2005-01-07, 00:00 authored by Andrés García-Granados, María C. Gutiérrez, Antonio Martínez, Francisco RivasTwo new 7-epi-eudesmane derivatives, together with two
new germacrane compounds, have been isolated from the
microbial-transformation of a (1α,10β),(4β,5α)-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
1α-hydroxy-(4β,5α)-epoxygermacr-9(E)-ene intermediate and
a subsequent cyclization process is proposed in order to
explain the formation of the 7-epi-eudesmane compounds.