Asymmetric Synthesis of Diazepino-?-lactams by [2 + 2] Cycloaddition of an ?Evans-Sjogven? Ketene with 1H-1,2-Diazepines
作者:Marc Muller、Daniel Bur、Th�ophile Tschamber、Jacques Streith
DOI:10.1002/hlca.19910740410
日期:1991.6.19
underwent non-concerted stereo specific [2 + 2] cycloadditions with the (Z)-imine moiety of diazepines 2, leading thereby with good diastereoselection to the trans-β-lactam adducts 3 (major) and 4 (minor). The absolute configuration of the major cycloadduct 3a was determined by an X-ray analysis. Its formation is discussed in terms of minimisation of steric interaction in the two transition states which
手性恶唑烷酮1的乙烯酮衍生物与非氮杂2的(Z)-亚胺部分进行了未经证实的立体特异性[2 + 2]环加成反应,从而导致反式-β-内酰胺加合物3(主要)和4(小)。通过X射线分析确定主要环加合物3a的绝对构型。根据在两个过渡态中的空间相互作用的最小化来讨论其形成,其依次给出两性离子中间体和最终的环加合物。