Abstract: | Experiments on the competitive incorporation of farnesol-stereoisomers into cantharidin Farnesol ( 2 ) has been demonstrated to be an efficient precursor for cantharidin ( 1 ), into which it is transformed by elimination of C(1), C(5), C(6), C(7) and C(7′) 1]. The following incorporation experiments with doubly labelled (3H and 14C) stereoisomers of farnesol present strong evidence that (E,E)- farnesol ((E,E)- 2 ) in fact is the precursor for cantharidin, whereas (2E, 6Z)- 2 and (Z,Z)- 2 are not utilized for the biosynthesis of cantharidin. A possible mechanism for the incorporation of (2Z,6E)-farnesol ((2Z,6E)- 2 ) to an extent of 56,8% relative to (E,E)- 2 is discussed. |