3,4-Dihydroxy-2,3,5-trimethyl-6-oxo-cyclohexa-1,4-dienecarboxylic acid 2-trimethylsilanyl-ethyl ester 、 2,2,2-Trichloroethyl 4-[tert-butyl(dimethyl)silyl]oxy-2-methoxy-3,6-dimethyl-5-[(1-methylpiperidin-1-ium-1-yl)methyl]benzoate;trifluoromethanesulfonate 在
四丁基氟化铵 作用下,
以
四氢呋喃 、
二氯甲烷 为溶剂,
反应 3.5h,
以95%的产率得到(4R,9aS)-4,4a-Dihydroxy-6-methoxy-3,4,5,8,9a-pentamethyl-1-oxo-4,4a,9,9a-tetrahydro-1H-xanthene-2,7-dicarboxylic acid 7-(2,2,2-trichloro-ethyl) ester 2-(2-trimethylsilanyl-ethyl) ester