[(2R,4S,6R,8S,10S)-8-[2-[(4-methoxyphenyl)methoxy]ethyl]-4-methyl-4-triethylsilyloxy-2-[(Z)-2-trimethylsilyloxybut-2-enyl]-1,7-dioxaspiro[5.5]undecan-10-yl] acetate 、
(2R,3S)-4-[(2S,4S,6S,8R,10S)-10-(tert-Butyl-dimethyl-silanyloxy)-8-(tert-butyl-diphenyl-silanyloxymethyl)-4-methoxy-1,7-dioxa-spiro[5.5]undec-2-yl]-3-(4-methoxy-benzyloxy)-2-methyl-butyraldehyde 在
三氟化硼乙醚 作用下,
以
二氯甲烷 为溶剂,
以69%的产率得到[(2R,4S,6R,8S,10S)-2-[(3S,4R,5S,6S)-7-[(2R,4S,6S,8S,10S)-4-[tert-butyl(dimethyl)silyl]oxy-2-[[tert-butyl(diphenyl)silyl]oxymethyl]-10-methoxy-1,7-dioxaspiro[5.5]undecan-8-yl]-4-hydroxy-6-[(4-methoxyphenyl)methoxy]-3,5-dimethyl-2-oxoheptyl]-8-[2-[(4-methoxyphenyl)methoxy]ethyl]-4-methyl-4-triethylsilyloxy-1,7-dioxaspiro[5.5]undecan-10-yl] acetate