General, Robust, and Stereocomplementary Preparation of β-Ketoester Enol Tosylates as Cross-Coupling Partners Utilizing TsCl−<i>N</i>-Methylimidazole Agents
作者:Hidefumi Nakatsuji、Kanako Ueno、Tomonori Misaki、Yoo Tanabe
DOI:10.1021/ol800480d
日期:2008.6.5
(Z)-stereocomplementary enol tosylation of beta-ketoesters using TsCl- N-methylimidazole (NMI)-Et3N or LiOH. TsCl coupled with NMI formed a highly reactive N-sulfonylammonium intermediate. Stereocongested secondary alcohols were smoothly sulfonylated using Ts(Ms)Cl-NMI-Et3N. beta-Ketoesters underwent (E)-selective tosylation using TsCl-NMI-Et3N and (Z)-selective tosylation using TsCl-NMI-LiOH (total
我们已经开发了使用TsCl-N-甲基咪唑(NMI)-Et3N或LiOH进行β-酮酸酯的(E)-或(Z)-立体互补烯醇甲苯磺酸酯化的通用,可靠且经济高效的方法。TsCl与NMI偶联形成高反应性的N-磺酰胺基中间体。使用Ts(Ms)Cl-NMI-Et3N将立体拥挤的仲醇顺利磺酰化。β-酮酸酯使用TsCl-NMI-Et3N进行(E)选择性甲苯磺酰化,使用TsCl-NMI-LiOH进行(Z)选择性甲苯磺酰化(共23个实例;收率60%-99%)。使用烯醇甲苯磺酸盐的立体定向Negishi和Sonogashira偶联成功进行,得到了三取代的α,β-不饱和酯。