methyl (2Z)-4-[(1R,3aS,5S,11R,14aS)-3a,4,5,7-tetrahydro-8-hydroxy-13-[(2E)-4-hydroxy-3-methylbut-2-en-1-yl]-3,3,11-trimethyl-11-(4-methylpent-3-en-1-yl)-7,15-dioxo-3H,11H-1,5-methanofuro[3,4-g]pyrano[3,2-b]xanthen-1-yl]-2-methylbut-2-enoate 在
4-二甲氨基吡啶 、
对甲苯磺酰氯 作用下,
以
二氯甲烷 为溶剂,
反应 8.0h,
以88%的产率得到methyl (2Z)-4-[(1R,3aS,5S,11R,14aS)-13-[(2E)-4-chloro-3-methylbut-2-en-1-yl]-3a,4,5,7-tetrahydro-8-hydroxy-3,3,11-trimethyl-11-(4-methylpent-3-en-1-yl)-7,15-dioxo-3H,11H-1,5-methanofuro[3,4-g]pyrano[3,2-b]xanthen-1-yl]-2-methylbut-2-enoate