title: N-pyrrolylketene: a nonconjugated heteroarylketene.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6 Canada.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Islami
authors.forename: Annette D
authors.initials: AD
authors.lastname: Allen
authors.forename: Sinisa
authors.initials: S
authors.lastname: Vukovic
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Tidwell
mesh_terms: D005030:Ethylenes / Q000138:chemical synthesis* / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D047090:beta-Lactams / Q000737:chemistry*
chemical_list: D005030:Ethylenes; D007659:Ketones; C556392:N-pyrrolylketene; D011758:Pyrroles; D047090:beta-Lactams; C008223:ketene