重氮甲烷 、
4'-(2-Carboxy-2-methylpropyl)-4,4,4'-trimethyl-5-oxotetrahydrofuran-2-spiro-cyclopentane-2'-carboxylic acid 以
乙醚 为溶剂,
反应 2.0h,
以56%的产率得到8-(2-Methoxycarbonyl-2-methyl-propyl)-3,3,8-trimethyl-2-oxo-1-oxa-spiro[4.4]nonane-6-carboxylic acid methyl ester