4-(((E)-5-((5'R)-4-hydroxy-4',4'-dimethylspiro[furo[3,2-g]chromene-7,2'-[1,3]dioxolan]-5'-yl)-3-methylpent-2-en-1-yl)oxy)-7H-furo[3,2-g]chromen-7-one 、
(E)-8-bromo-2,3-O-isopropylidene-2,6-dimethyl-6-octene-2,3-diol 在
monopotassium carbonate 、
三乙胺 作用下,
以
四氢呋喃 为溶剂,
反应 24.0h,
以40%的产率得到4-[(E)-5-[(4R)-5,5-dimethyl-4'-[(E)-3-methyl-5-(2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)pent-2-enoxy]spiro[1,3-dioxolane-2,7'-furo[3,2-g]chromene]-4-yl]-3-methylpent-2-enoxy]furo[3,2-g]chromen-7-one