Stereospecific Cyclopropanation of Highly Substituted C−C Double Bonds Promoted by CrCl<sub>2</sub>. Stereoselective Synthesis of Cyclopropanecarboxamides and Cyclopropyl Ketones
作者:José M. Concellón、Humberto Rodríguez-Solla、Carmen Méjica、Elena G. Blanco
DOI:10.1021/ol070896d
日期:2007.8.1
(Z)-alpha,beta-enamides in which the C-C double bond is di-, tri-, or tetrasubstituted. In all cases the process is completely stereospecific and only a single diastereoisomer is obtained. In addition, cyclopropyl ketones were readily prepared by reaction of the cyclopropanecarboxamides (derived from morpholine) obtained with a range of organolithium compounds. A mechanism has been proposed to explain the cyclopropanation
我们在这里描述了CrCl(2)促进的α,β-不饱和酰胺的环丙烷化。该反应可以在其中CC双键被二,三或四取代的(E)-或(Z)-α,β-烯酰胺上进行。在所有情况下,该过程都是完全立体定向的,并且仅获得单个非对映异构体。另外,通过使所获得的环丙烷甲酰胺(衍生自吗啉)与一定范围的有机锂化合物反应,可以容易地制备环丙基酮。已经提出了解释环丙烷化反应的机理。