(2R)-3,4-dibenzyloxy-2-[(1S)-1,2-dihydroxyethyl]-2H-furan-5-one 、 (20R,22R)-14α-hydroxy-2β,3β:20,22-bis(isopropylidenedioxy)-24-oxo-25,26,27-trinor-5β-cholest-7-en-6-one 在
对甲苯磺酸 作用下,
以
苯 为溶剂,
反应 24.33h,
以15%的产率得到(5R)-3,4-dibenzyloxy-5-{(2S,4S)-2-[(20R,22R)-14α-hydroxy-2,3:20,22-bis(isopropylidenedioxy)-6-oxo-24,25,26,27-tetranor-5β-cholest-7-en-23-yl]-1,3-dioxolan-4-yl}furan-2(5H)-one