2,2-Dimethyl-5-(triphenylphosphoranylidene)acetyl-1,3-dioxan-4,6-dione (3) is a new activated β-ketoacyl equivalent, readily prepared in quantitative yield by reaction of Meldrum’s acid with the stable ylide Ph₃PCCO. Its reaction with α-amino esters affords the corresponding N-(β-ketoacyl)amino ester ylides which, when treated with aldehydes and KOtBu, undergo a simultaneous Wittig olefination cum Dieckmann cyclisation to yield the respective 3-enoyltetramic acids.

中文翻译：

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使用Meldrum酸的新酰基内酯共轭物快速合成3-enoyltetramic酸

2,2-二甲基-5-（三苯基正膦亚基）乙酰基-1,3-二恶烷-4,6-二酮（3）是一种新的活化的β-酮酰基当量，易于通过Meldrum酸与稳定的叶立德反应以定量收率制得Ph ₃ PCCO。它与α氨基酯反应，得到相应的Ñ - （β酮酰基）氨基酯叶立德，当与醛和KO处理吨卜，经历同时Wittig烯化暨迪克曼环化，得到相应的3- enoyltetramic酸。