乙酸酐 、
methyl 5-hydroxy-6,10-dimethoxy-2-(trifluoromethyl)-4,5-dihydro-2,5-methanofuro[3,2-h][1,3]benzoxathiepine-4-carboxylate 在
硫酸 作用下,
反应 0.02h,
以38%的产率得到methyl 5-acetoxy-8-acetyl-6,10-dimethoxy-2-(trifluoromethyl)-4,5-dihydro-2,5-methanofuro[3,2-h][1,3]benzoxathiepine-4-carboxylate