A short synthesis of 3-enoyltetramic acids employing a new acyl ylide conjugate of Meldrum’s acid
作者:Kevin Lovmo、Steffen Dütz、Marina Harras、Robert G. Haase、Wolfgang Milius、Rainer Schobert
DOI:10.1016/j.tetlet.2017.11.025
日期:2017.12
readily prepared in quantitative yield by reaction of Meldrum’sacid 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.
3‐Acyltetramic acids, including delicate 3‐oligoenoyl derivatives, such as the Penicillium metabolite ravenicacid, were prepared in two high‐yielding steps. Reaction of tetramicacids with the ylide Ph3PCCO afforded exclusively the corresponding 3‐acylylidenetetramic acids. These were amenable to Wittig olefinations with aliphatic, aromatic, saturated and unsaturated aldehydes after deprotonation
3-Acyltetramic acid,包括易碎的3-oligoenoyl衍生物,例如青霉代谢产物鼠尾草酸,是通过两个高产率步骤制备的。丁二酸与叶立德Ph 3 PCCO的反应仅提供了相应的3-酰亚乙基四丁酸。这些在用KO t Bu去质子化之后适合于用脂族,芳族,饱和和不饱和醛进行的维蒂希(Wittig)烯化。由于其简单性,对pH敏感基团的选择性和耐受性,该方法优于Jones和Yoshii建立的酰化方案。它也适用于3-酰基电子酸的合成。新的3-寡烯酰基四酸显示出结构依赖性的抗微生物和细胞毒性活性。