Biosynthesis of isofucosterol from [2- 13 C 2 H 3 ]acetate and [1,2- 13 C 2 ]acetate in tissue cultures of Physalis peruviana—the stereochemistry of the hydride shift from C-24 to C-25

Migration of the hydrogen atom at C-24 of cycloartenol to C-25 from the Re-face of the double bond occurred in the biosynthesis of isofucosterol in cell cultures of Physalis peruviana fed [2-13C2H3]acetate and [1,2-13C2] acetate. This was verified by 13C n.m.r. spectroscopy.