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 ...
