Preparation of Cyclopenta-Fused N-, O-, and S-Heterocycles by Lewis Acid Catalyzed Nazarov Reaction
作者:Ernesto Occhiato、Laura Bartali、Paolo Larini、Antonio Guarna
DOI:10.1055/s-2007-965965
日期:2007.6
products of carbonylative coupling between lactam-, lactone- and thiolactone-derived vinyl triflates and alkenylboronic acids are suitable substrates for the Lewis acid catalyzed Nazarov reaction. The most efficient Lewis acids for the Nazarov reaction are scandium(III) and indium(III) triflates (3-15 mol%) in 1,2-dichloroethane, which provide the Nazarov products in moderate to excellent yield (53-86%)
内酰胺、内酯和硫代内酯衍生的乙烯基三氟甲磺酸酯和烯基硼酸之间的羰基化偶联产物是路易斯酸催化的纳扎罗夫反应的合适底物。用于 Nazarov 反应的最有效的路易斯酸是 1,2-二氯乙烷中的三氟甲磺酸钪 (III) 和三氟甲磺酸铟 (III) (3-15 mol%),它们以中等至优异的产率 (53-86%) 提供 Nazarov 产物. 电环化速率还取决于杂原子(N、O、S)和 N-保护基团。总的来说,整个过程是快速合成六氢[1]吡啶、-环戊[B]吡喃和-环戊[B]噻喃,因为它们形成了几种天然分子的结构核心,因此值得关注。