Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6 Canada.
Org Lett. 2011 Feb 4;13(3):494-7. doi: 10.1021/ol102837n. Epub 2010 Dec 29.
N-Pyrrolylketene (5) is calculated to be destabilized and nonconjugated, with a preferred geometry with the pyrrolyl ring orthogonal to the ketenyl group. Ketene 5 is generated from N-pyrrolylacetic acid (7) with use of Mukaiyama's reagent, and reacts with imines forming β-lactams 10, with a product ratio correlation of log(cis/trans) with σ(+). Photolysis of N-diazoacetylpyrrole (14) in MeOH gives methyl N-pyrrolylacetate (15) from 5 and also ester 17, evidently by trapping of 2-(1-pyrrolylketene) (21), formed by a new vinylogous Wolff rearrangement.
N-吡咯甲烯（5）被计算为不稳定和非共轭的，其优选的几何形状是吡咯环与甲烯基基团正交。甲烯 5 是由 N-吡咯乙酸（7）与 Mukaiyama 试剂生成的，与亚胺反应形成β-内酰胺 10，其产物比例与 σ(+)的关系呈对数（顺/反）。在甲醇中用光解 N-重氮乙酰基吡咯（14）得到甲基 N-吡咯基乙酸酯（15），这显然是通过捕获 2-（1-吡咯甲烯）（21）而形成的，21 是由新的乙烯基 W-重排形成的。
