title: A general and efficient cobalt(II)-based catalytic system for highly stereoselective cyclopropanation of alkenes with α-cyanodiazoacetates.
abstract: [Co(P1)], the cobalt(II) complex of the D(2)-symmetric chiral porphyrin 3,5-Di(t)Bu-ChenPhyrin, is an effective catalyst for catalyzing asymmetric olefin cyclopropanation with the acceptor/acceptor-type diazo reagent α-cyanodiazoacetates. The [Co(P1)]-catalyzed reaction is versatile and suitable for both aromatic and aliphatic olefins with varied electronic properties, including electron-rich and -poor olefins. The Co(II)-based catalytic system can be operated in a one-time protocol under mild conditions, affording the desired cyclopropane products in high yields with both high diastereo- and enantioselectivity. The resulting enantiomerically enriched 1,1-cyclopropanenitrile esters provide convenient access to a number of densely functionalized chiral cyclopropane derivatives, including α-cyclopropyl-β-amino acids.
authors.affiliation: Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, USA.
authors.forename: Shifa
authors.initials: S
authors.lastname: Zhu
authors.forename: Xue
authors.initials: X
authors.lastname: Xu
authors.forename: Jason A
authors.initials: JA
authors.lastname: Perman
authors.forename: X Peter
authors.initials: XP
authors.lastname: Zhang