Methyl 8-methoxy-6-(2-methoxy-2-oxoethyl)-2-methylidene-3,4-dihydrochromene-7-carboxylate 、 在
2,4,6-三甲基吡啶 、
trifluoromethanesulfonic acid anhydride 作用下,
以
乙腈 为溶剂,
以20 mg的产率得到8-methoxy-7-methoxycarbonyl-6-(methoxycarbonylmethyl)chroman-2-spiro-2'-[7'-methoxy-4'-methoxycarbonyloxy-9'-methoxymethoxy-5'-phenylthio-2',3'-dihydronaphtho[1,2-b]furan]