[3 + 3]-Carbocyclizations of nitroallylic esters and enamines with stereoselective formation of up to six new stereogenic centers
作者:Dieter Seebach、Martin Missbach、Giorgio Calderari、Martin Eberle
DOI:10.1021/ja00177a026
日期:1990.10
and intermediates, which can be trapped under certain conditions, as well as previous investigations of single steps of the in situ reaction sequence involved in the carbocyclization are used to arrive at a tentative proposal for the steric course of these steps: (i) intermolecular coupling of the trigonal centers of enamine and nitroolefin with preferred relative topicity like, (ii) intramolecular coupling
讨论了导致观察到的产物的复杂反应序列的机制。可以在某些条件下捕获的产物和中间体的结构,以及先前对参与碳环化的原位反应序列的单个步骤的研究,用于得出这些步骤的空间过程的初步建议: (i) 烯胺和硝基烯烃的三角中心的分子间偶联,具有优选的相对局部性,(ii) 中间体烯胺中的三角中心的分子内偶联,(iii) 硝基阴离子部分的质子化,和 (iv) 的质子化烯胺(在单环产品的情况下)