title: Enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents via Co(II)-based metalloradical catalysis.
abstract: The cobalt(II) complex of a new D(2)-symmetric chiral porphyrin 3,5-diMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents, such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range of terminal aromatic and related conjugated alkynes with varied steric and electronic properties, providing the corresponding trisubstituted cyclopropenes in high yields with excellent enantiocontrol of the all-carbon quaternary stereogenic centers. In addition to mild reaction conditions, the Co(II)-based metalloradical catalysis for cyclopropenation features a high degree of functional group tolerance.
authors.affiliation: Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, United States.
authors.forename: Xin
authors.initials: X
authors.lastname: Cui
authors.forename: Xue
authors.initials: X
authors.lastname: Xu
authors.forename: Hongjian
authors.initials: H
authors.lastname: Lu
authors.forename: Shifa
authors.initials: S
authors.lastname: Zhu
authors.forename: Lukasz
authors.initials: L
authors.lastname: Wojtas
authors.forename: X Peter
authors.initials: XP
authors.lastname: Zhang