Biosynthetic precursors for α- and β-cembrenediol formation in tobacco

Article abstract of DOI:10.1016/0031-9422(88)80426-6

After survey of the α- and β-cembrenediol (CBD) content of different plant organs of tobacco, calyces were selected for tracer administration. (R/S)-[2-¹⁴C]-Mevalonic acid dibenzylethylenediamine salt gave incorporations of 0.10% into α-CBD and 0.03% into gb-CBD. Good incorporations (α-CBD 2.30%, β-CBD 0.93%) of sodium [1-¹⁴C] acetate were found. all-(E)-[2-¹⁴C]-Geranylgeraniol gave incorporations of 1.49 and 1.53% into the cembrenediols in two experiments, though radiochemical distribution among α- and β- forms was variable. Using the Kato cyclization method, a sample of (R/S)-[3-¹⁴C]-cembrene was prepared and was incorporated into the cembrenediols (0.58 and 0.42% overall, with variable distribution among α- and β-isomers). Methods for making (R/S)-[2-²H], [15-²H] and ent- (1R)-[20-³H] cembrene are described. The possible involvement of ent-(1R,3S)-casbene in the formation of (1S)-cembrene is discussed.