3'R,4'R-di-O-(-)-camphanoyl-2,2',2'-trimethyldihydropyrano[2,3-f]chromone 在
N-溴代丁二酰亚胺(NBS) 、
间氯过氧苯甲酸 作用下,
以
四氯化碳 为溶剂,
反应 5.0h,
以23%的产率得到[(9R,10R)-2-(bromomethyl)-8,8-dimethyl-4-oxo-9-[(1S,4R)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carbonyl]oxy-9,10-dihydropyrano[2,3-f]chromen-10-yl] (1S,4R)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxylate