A Flexible Synthesis of Methyl 4-Oxobutanoates and Their Derivatives Ring cleavage of several methyl 2-trimethylsiloxycyclopropanecarboxylates 3 provides rather sensitive methyl 4-oxobutanoates (ß-formyl esters) 4 in excellent yields. Siloxycyclopropanes 3 are easily available either directly from the corresponding silyl enol ethers 2 and methyl diazoacetate or by alkylation of deprotonated cyclopropanes 3. A highly efficient one-pot procedure affords methyl 4,4-dimethoxybutanoates 5, which can be converted into protected 4-hydroxybutanals 7 and 8 by standard methods.
一种灵活合成甲基4-氧酮
丁酸酯及其衍
生物的方法。几种甲基2-三甲基
硅氧基
环丙烷羧酸酯3的环裂解反应可以在优异的产率下得到相当敏感的甲基4-氧酮
丁酸酯(β-羟基酯)4。
硅氧
环丙烷3可以直接从相应的
硅醇醚2和甲基二氮
乙酸酯获得,也可以通过对脱质子化的
环丙烷3进行烷基化获得。一种高效的一锅法程序可以提供甲基4,4-二甲氧基
丁酸酯5,后者可以通过标准方法转化为保护的
4-羟基丁醛7和8。