trans-crotonic anhydride 、 Acetic acid (3S,3aS,6R,6aR,9bS)-8-hydroxy-3,6-dimethyl-2,3,3a,4,5,6,6a,7,8,9b-decahydro-azuleno[4,5-b]furan-6-yl ester 在
4-二甲氨基吡啶 作用下,
以
二氯甲烷 为溶剂,
反应 1.25h,
以4%的产率得到(E)-But-2-enoic acid (3S,3aS,6R,6aR,8R,9bS)-6-acetoxy-3,6,9-trimethyl-2-oxo-2,3,3a,4,5,6,6a,7,8,9b-decahydro-azuleno[4,5-b]furan-8-yl ester