Synthesis of 2-Alkylidenecyclopentanones via Palladium-Catalyzed Carbopalladation/Ring Expansion of 1-(1-Alkynyl)cyclobutanols
作者:Richard C. Larock、Ch. Kishan Reddy
DOI:10.1021/jo010577e
日期:2002.4.1
The palladium-catalyzed cross-coupling of aryl halides or vinylic halides or triflates and 1-(1-alkynyl)cyclobutanols affords good yields of stereoisomerically pure 2-arylidene- or 2-(2-alkenylidene)cyclopentanones, respectively. The process involves (1) oxidative addition of the organic halide or triflate to Pd(0), (2) regioselective, intermolecular carbopalladation of the carbon-carbon triple bond
芳基卤化物或乙烯基卤化物或三氟甲磺酸酯与1-(1-炔基)环丁醇的钯催化交叉偶联分别提供了良好的立体异构纯的2-亚芳基-或2-(2-链烯基)环戊酮。该方法涉及(1)将有机卤化物或三氟甲磺酸酯氧化添加到Pd(0)中,(2)1-(1-炔基)环丁醇的碳-碳三键的区域选择性分子间碳钯反应制得乙烯基钯中间体,(3)区域选择性环扩展成palladacycle,以及(4)还原消除2-亚烷基环戊酮,同时再生Pd(0)催化剂。通常,通过使用10 mol%的Pd(OAc)(2),20 mol%的PPh(3),2当量的芳基或乙烯基碘或三氟甲磺酸乙烯酯,2当量的二异丙基乙胺,