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Regioselectivity and Deuterium Isotope Effects in Geraniol Hydroxylation by the Cytochrome P‐450 Monooxygenase from Catharanthus roseus (L.) G. D ON
Author(s) -
Fretz Heinz,
Woggon WolfDietrich
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690822
Subject(s) - chemistry , hydroxylation , geraniol , regioselectivity , catharanthus roseus , kinetic isotope effect , deuterium , stereochemistry , cytochrome , intramolecular force , dehydrohalogenation , organic chemistry , enzyme , catalysis , chromatography , biochemistry , physics , quantum mechanics , essential oil
The hydroxylation of geraniol ( 8 ) by cytochrome P‐450 (P‐450 Cath. ) from the subtropical plant Catharanthus roseus (L.) G. D ON was optimised to give 8‐hydroxygeraniol ( 9 ) as the single product in 35% yield. Incubations of different 13 C‐ and 2 H‐labelled geraniols revealed that H‐abstraction is completely regioselective in favour of the CH 3 group trans to the chain at C(6) of 8 . An intramolecular isotope effect k H / k D = 8.0 was determined, suggesting that H‐abstraction is one of the major rate‐contributing steps; however, the intermolecular isotope effect was surprisingly inverse at low conversion k H / k D = 0.50, indicating the existence of rate‐contributing steps preceding the first irreversible, isotope‐sensitive reaction in the sequence.