Enantiomerically Pure α-Alkylidene β-Amino Esters from Asymmetric Addition of Metal Dienolates to <i>N</i>-Sulfinylimines
作者:J. L. García Ruano、I. Fernández、M. del Prado Catalina、J. A. Hermoso、J. Sanz-Aparicio、M. Martínez-Ripoll
DOI:10.1021/jo972303q
日期:1998.10.1
these mixtures followed by isomerization of the double bond with Na(2)CO(3) allowed the synthesis of the optically pure (E)-alpha-ethylidene-beta-amino ester 10 in quite high overall yield. The addition of the lithium dienolate to sulfinylimines in the absence of the Lewis catalysts yielded mixtures containing important amounts of the optically pure N-arylsulfinyl alpha-ethylidene-beta-amino esters
在不同条件下,使3-丁烯酸甲酯的二烯酸锂与对映体纯的N-芳基亚磺酰基苯基亚胺(1和2)反应。反应是完全区域选择性的-CC偶合发生在二烯酸的2位上-高立体选择性发生在亚氨基碳上。在存在不同的路易斯酸(ZnCl(2),ZnBr(2)和ScTf(3))的情况下,获得了两种α-乙烯基,β-芳基亚磺酰基氨基酯(C-alpha上的末端)的混合物,其立体选择性取决于芳基亚磺酰基部分的性质和所用的路易斯酸。这些混合物的脱亚磺酰化,然后用Na(2)CO(3)进行双键异构化,从而可以以很高的总收率合成光学纯的(E)-α-亚乙基-β-氨基酯10。