(R)-4-[(2S,6R)-6-((2S,6R)-6-{(E)-3-[(2S,6S)-6-((2R,3R)-3-Benzyloxymethoxy-2-hydroxy-butyl)-2-methoxy-3-oxo-tetrahydro-pyran-2-yl]-3-methyl-but-1-enyl}-4-methylene-tetrahydro-pyran-2-ylmethyl)-4-methylene-tetrahydro-pyran-2-yl]-3-hydroxy-butyric acid 在
lithium tetrafluoroborate 作用下,
以
水 、
乙腈 为溶剂,
生成 (1R,3S,7R,8E,11S,15S,17R,21R,23S)-11,21-dihydroxy-17-[(1R)-1-hydroxyethyl]-10,10-dimethyl-5,25-dimethylidene-18,27,28,29-tetraoxatetracyclo[21.3.1.13,7.111,15]nonacos-8-ene-12,19-dione