TiCl<sub>4</sub>-<i>n</i>-Bu<sub>3</sub>N-mediated cascade annulation of ketones with α-ketoesters: a facile synthesis of highly substituted fused γ-alkylidene-butenolides
作者:Megha N. Palange、Rajesh G. Gonnade、Ravindar Kontham
DOI:10.1039/c9ob00649d
日期:——
to biologically relevant natural products were prepared from readily accessible ketone and α-ketoester building blocks. The highly step-economic cascade nature, good substrate scope, easy access to complex products with good to excellent yields, gram-scalability, demonstration of synthetic utility, and unambiguous structuralconfirmation through X-ray crystallography analyses and analogy are the salient
TiCl4‐Et3N‐mediated condensation of ketones with methyl pyruvate afforded γ‐alkylidene butenolides via a tandem cross‐aldol addition/dehydroxylation/intramolecular lactonization process in one‐pot. The application of the methodology to the straightforward synthesis of elem‐1,3,7,8‐tetraen‐8,12‐olide, chloranthalactone A, and dehydromenthofurolactone, is demonstrated.
TiCl 4 - Et 3 N介导的酮与丙酮酸甲酯的缩合反应通过一个锅中的串联交叉羟醛加成/脱羟基/分子内内酯化过程提供了γ-亚烷基丁烯内酯。演示了该方法在直接合成elem-1,3,7,8-tetraen-8,12-内酯,氯半乳糖苷A和脱氢薄荷脑内酯中的应用。
Synthesen in der Reihe der Anthelmintika. II. Mitteilung