Mechanism of the conversion of fucosterol epoxide into desmosterol in insects. Stereochemical fate of the diastereotopic C-26 and C-27 methyl groups of the epoxide
Abstract
The conversion of fucosterol epoxide (1) into desmosterol (2), by the cell-free preparation obtained from the guts of larvae of the silkworm, Bombyx mori, is stereospecific, where the isopropyl pro-R and pro-S methyl groups of (1) turn stereospecifically into (E)- and (Z)-methyl groups, respectively, of (2).