新法构建25—羟基油菜甾体的侧链

Novel Construction of Sidechain of 25 - Hydroxybrassinosteroid

油菜甾体例如油菜甾醇内酯(1a)和24-表油菜甾醇内酯(2a)是一族新型的甾体植物生长激素(植物生长调节剂).它们具有提高植物生长调节和应变的活性并具有农作物增产效果,已愈益受到国际上的广泛重视[1].

The sidechain of (24R) - 24 - methyl - 25 - hydroxybrassinosteroid 13 has been synthesized in an overall yields of 10.9 % from methyl hyodeoxycholanate 3 in 10 steps with the introduction of the hydroxyl group to the 25 - C by KMnO4 and the improved Sharpless asymmetric dihydroxylation as the two key steps.