(1R,4S)-1-{(S)-2-[(1S,2S,6S)-6-tert-Butoxy-2-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-methylene-cyclohexyl]-1-methoxymethoxy-ethyl}-4-(tert-butyl-dimethyl-silanyloxy)-2,6,6-trimethyl-cyclohex-2-enol 在
2,3,5-三甲基吡啶 、
三氟甲磺酸三甲基硅酯 作用下,
以
甲苯 为溶剂,
反应 2.0h,
以82%的产率得到(4S,5R,8S)-4-[(1S,2S,6S)-6-tert-Butoxy-2-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-methylene-cyclohexylmethyl]-8-(tert-butyl-dimethyl-silanyloxy)-6,10,10-trimethyl-1,3-dioxa-spiro[4.5]dec-6-ene