((2S,3R)-6-{(4S,5S,6R)-6-[(1S,4S)-4-(3-Benzyloxy-phenyl)-4-methoxy-1-methyl-butyl]-2,2,5-trimethyl-[1,3]dioxan-4-ylmethyl}-6-hydroxy-3,5,5-trimethyl-tetrahydro-pyran-2-yl)-acetic acid methyl ester 在
acid 作用下,
生成
{(2S,3R,6S,8R,9S)-8-[(1S,4S)-4-(3-Benzyloxy-phenyl)-4-methoxy-1-methyl-butyl]-3,5,5,9-tetramethyl-1,7-dioxa-spiro[5.5]undec-10-en-2-yl}-acetic acid methyl ester 、 {(2S,3R,6R,8R,9S,10S)-8-[(1S,4S)-4-(3-Benzyloxy-phenyl)-4-methoxy-1-methyl-butyl]-10-hydroxy-3,5,5,9-tetramethyl-1,7-dioxa-spiro[5.5]undec-2-yl}-acetic acid methyl ester 、 {(2S,3R,6S,8R,9S,10S)-8-[(1S,4S)-4-(3-Benzyloxy-phenyl)-4-methoxy-1-methyl-butyl]-10-hydroxy-3,5,5,9-tetramethyl-1,7-dioxa-spiro[5.5]undec-2-yl}-acetic acid methyl ester