丙酸甲酯 、
Acetic acid (2S,3S,4S,5S,6R,8R,9R,11R)-9-benzyloxy-2-ethyl-3-hydroxy-3,5,9,11-tetramethyl-8-((R)-1-methyl-2-oxo-ethyl)-1,7-dioxa-spiro[5.5]undec-4-yl ester 在
zirconocene dichloride 、
lithium diisopropyl amide 作用下,
以
四氢呋喃 为溶剂,
以54%的产率得到(2R,3S,4S)-4-((2R,3R,5R,6R,8S,9S,10S,11S)-10-Acetoxy-3-benzyloxy-8-ethyl-9-hydroxy-3,5,9,11-tetramethyl-1,7-dioxa-spiro[5.5]undec-2-yl)-3-hydroxy-2-methyl-pentanoic acid methyl ester