Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George St., Toronto ON, M5S 3H6, Canada.
Chemistry. 2010 Apr 6;16(13):4100-9. doi: 10.1002/chem.200902748.
In this contribution, aminocyclobutanes, as well as eight-membered enamide rings, have been made from N-vinyl beta-lactams. The eight-membered products have been formed by a [3,3]-sigmatropic rearrangement, whereas the aminocyclobutanes have been derived from a domino [3,3]-rearrangement/6pi-electrocyclisation process. The aminocyclobutanes have been obtained in a highly diastereoselective fashion. The cyclobutane ring system tolerates fusion even if adjacent quaternary centres are present. Systems containing up to four fused rings are readily accessible. The reaction profile has been investigated by using Gaussian 03. This study suggests that two reaction pathways for aminocyclobutane formation are possible. In one pathway the [3,3]-sigmatropic rearrangement is the rate-limiting step and in the second pathway the electrocyclisation is rate limiting. Taken together, these reactions should facilitate the construction of fused heterocycles.
在本研究中，我们从 N-乙烯基 β-内酰胺出发合成了氨基环丁烷和八元烯酰胺环。八元产物通过[3,3]-σ重排形成，而氨基环丁烷则通过串联[3,3]-重排/6π-电环化过程生成。氨基环丁烷以高度立体选择性的方式获得。即使存在相邻的季碳原子，环丁烷环系统也能耐受稠合。易于获得含有多达四个稠合环的系统。使用 Gaussian 03 研究了反应轮廓。该研究表明，氨基环丁烷形成可能存在两种反应途径。在一种途径中，[3,3]-σ重排是限速步骤，而在第二种途径中，电环化是限速步骤。总的来说，这些反应应该有助于构建稠合杂环。
