Stereochemical disposition of the geminal dimethyl groups in the enzymaticcyclization of geranyl diphosphate to (+)-bornyl diphosphate by recombinant (+)-bornyl diphosphate synthase from Salvia officinalis

Regiospecifically deuterated geranyl diphosphate, in concert with NMR spect rometry, was employed to demonstrate that the trans-methyl group (C8) of ge ranyl diphosphate becomes the C9 carbon of (+)-bornyl diphosphate (geminal methyl syn to the diphosphate moiety) and that the cis-methyl group (C9) be comes the C8 (geminal methyl anti to the diphosphate). The syntheses of the relevant substrates and products, with accompanying spectrometric data are provided. (C) 2001 Elsevier Science Ltd. All rights reserved.