Catalytic, enantioselective [4+2]-cycloadditions of ketene enolates and o-quinones:: Efficient entry to chiral, α-oxygenated carboxylic acid derivatives
Catalytic, enantioselective [4+2]-cycloadditions of ketene enolates and o-quinones:: Efficient entry to chiral, α-oxygenated carboxylic acid derivatives
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DOI：
10.1021/ja058077g
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发表时间：
2006-02-15
影响因子：
15
通讯作者：
Lectka, T
中科院分区：
文献类型：
--
作者：
Bekele, T;Shah, MH;Lectka, T
我们报道了用金鸡纳生物碱衍生物作催化剂，邻醌与乙烯酮烯醇化物（来自易得的酰氯）的催化的，对映选择性的[4 + 2]-环加成反应，得到了高对映体过量（ee）和良好的产率。这些反应的热力学驱动力部分是由于产物芳香性的恢复。所得的手性双环加合物可以以多种有用的方式进行合成操作，例如以提供α-含氧羧酸衍生物的灵活合成。
We report catalytic, enantioselective [4 + 2]-cycloadditions ofo-quinones with ketene enolates (derived from readily available acid chlorides) using cinchona alkaloid derivatives as catalysts to produce products in high enantiomeric excess (ee) and good to excellent yields. The thermodynamic driving force for these reactions is due in part to the restoration of aromaticity to the products. The resulting chiral, bicycloadducts can be synthetically manipulated in a variety of useful ways, for example to provide a flexible synthesis of α-oxygenated carboxylic acid derivatives.