A method for the synthesis of cyclopropanes by regiospecific and regioselective magnesium carbenoid 1,3-CH insertion as the key reactions
作者:Hiroyuki Watanabe、Shingo Ogata、Tsuyoshi Satoh
DOI:10.1016/j.tet.2010.05.061
日期:2010.7
i-PrMgCl resulted in the formation of magnesium carbenoid. Highly regiospecific 1,3-CH insertion reaction was found to take place from each magnesium carbenoid to afford cyclopropanes. On the other hand, when the unsymmetrical ketones bearing an oxygen- or a nitrogen-functional group on the α-carbon were used in this procedure, the regioselective 1,3-CH insertion reaction proceeded mainly. Stereochemistry
衍生自不对称酮和氯甲基对甲苯基亚砜的1-氯乙烯基对甲苯基亚砜的两个几何异构体与乙酸叔丁酯的烯醇锂的加成反应分别得到加合物的单一非对映异构体。用i处理每个非对映异构体-PrMgCl导致形成类镁镁。发现每个镁类胡萝卜素都发生高度区域特异性的1,3-CH插入反应,从而生成环丙烷。另一方面,当在该方法中使用在α-碳上带有氧或氮官能团的不对称酮时,区域选择性的1,3-CH插入反应主要进行。讨论了加合物的立体化学,反应机理以及特异性和选择性的实质。