One-pot synthesis of <i>trans</i>-β-lactams from ferrocenylketene generated by thermal Wolff rearrangement

A series of β-lactams containing the ferrocene moiety were synthesized through the Staudinger reaction between ferrocenylketene generated by the thermal Wolff rearrangement of the corresponding diazo ketone and various imines. The stereochemical outcome has been investigated and the <i>trans</i>-products were isolated as the main products, opposite to the reported results by Bonini and coworkers. The absolute configuration of (±)-<i>trans</i>-1,4-diphenyl-3-ferrocenylazetidin-2-one (<b>3c</b>) was determined by X-ray analysis. The stereoselectivity is discussed from the viewpoint of the reaction mechanism.

本研究通过施陶丁格反应（Staudinger reaction）合成了一系列含二茂铁结构单元的β-内酰胺（β-lactams）：该反应以相应重氮酮经热沃尔夫重排（Wolff rearrangement）生成的二茂铁基乙烯酮与多种亚胺（imines）为反应物。本研究对该反应的立体化学结果进行了考察，最终分离得到的主产物为反式（trans）产物，这与Bonini及其同事此前报道的结果相悖。通过X射线分析（X-ray analysis）确定了(±)-反式-1,4-二苯基-3-二茂铁基氮杂环丁烷-2-酮（3c）的绝对构型。本文从反应机理的角度对该反应的立体选择性进行了探讨。