into the corresponding diene 5 which is hydrogenated to give predominantly the diequatorial dimethyl hexopyranoside 3. C6 of the latter is converted stepwise to the methyl ketone from which Prelog-Djerassi Lactone 8 and its 2-epimer 9 are prepared in 3:2 ration.
由甲基α,
D-吡喃葡萄糖苷得到的烯酮1被转化为相应的二烯5,该二烯5被氢化以主要得到二甲基二甲基己
吡喃糖苷3。后者的C6被逐步地转化为甲基酮,Prelog-Djerassi Lactone 8及其它从中被甲基化。以3:2的比例准备2-epimer 9。