such systems to α-pyrones was investigated in the case of the acrolein adduct, diethyl 2-formylcyclopropane-1,1-dicarboxylate. While its cyclopropane ring could not be isomerized to an olefin with aluminum chloride or by reactions catalyzed by transition metals and while photolysis led to a dihydrofuran derivative, pyrolysis in high vacuum at 550–575° afforded directly an α-pyrone, ethyl coumalate. Evidence
结果表明,
丙烯醛与
溴丙二酸酯在碱
金属醇盐存在下反应生成 2-甲酰基
环丙烷-1,1-二
羧酸酯,可用于类
固醇系列;因此,20-亚甲基21-醛以优异的产率得到相应的
环丙烷衍
生物。在
丙烯醛加合物、
2-甲酰基环丙烷-1,1-二羧酸二乙酯的情况下,研究了将此类系统转化为
α-吡喃酮的可能性。虽然它的
环丙烷环不能与
氯化铝或通过过渡
金属催化的反应异构化为烯烃,而光解导致二氢
呋喃衍
生物,但在 550-575° 的高真空下热解直接提供
α-吡喃酮,
香豆酸乙酯。提出了 3-乙氧羰基-
α-吡喃酮在该反应中作为中间体的证据。