methyl (1R,2R,5R,7S,8S,9R,10R,13R,14R,15R,18S)-7-hydroxy-1,2,6,6,9-pentamethyl-15-prop-1-en-2-yl-18-(trityloxymethyl)pentacyclo[11.7.0.02,10.05,9.014,18]icosane-8-carboxylate 、
乙酸酐 以
吡啶 为溶剂,
以78%的产率得到methyl (1R,2R,5R,7S,8S,9R,10R,13R,14R,15R,18S)-7-acetyloxy-1,2,6,6,9-pentamethyl-15-prop-1-en-2-yl-18-(trityloxymethyl)pentacyclo[11.7.0.02,10.05,9.014,18]icosane-8-carboxylate