title: D2-symmetric dirhodium catalyst derived from a 1,2,2-triarylcyclopropanecarboxylate ligand: design, synthesis and application.
abstract: Dirhodium tetrakis-(R)-(1-(4-bromophenyl)-2,2-diphenylcyclopropanecarboxylate) (Rh(2)(R-BTPCP)(4)) was found to be an effective chiral catalyst for enantioselective reactions of aryl- and styryldiazoacetates. Highly enantioselective cyclopropanations, tandem cyclopropanation/Cope rearrangements and a combined C-H functionalization/Cope rearrangement were achieved using Rh(2)(R-BTPCP)(4) as catalyst. The advantages of Rh(2)(R-BTPCP)(4) include its ease of synthesis, its tolerance to the size of the ester group in the styryldiazoacetates, and its compatibility with dichloromethane as solvent. Computational studies suggest that the catalyst adopts a D(2)-symmetric arrangement, but when the carbenoid binds to the catalyst, two of the p-bromophenyl groups on the ligands rotate outward to make room for the carbenoid and the approach of the substrate to the carbenoid.
authors: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors: Changming
authors: C
authors: Qin
authors: Vyacheslav
authors: V
authors: Boyarskikh
authors: Jørn H
authors: JH
authors: Hansen
authors: Kenneth I
authors: KI
authors: Hardcastle
authors: Djamaladdin G
authors: DG
authors: Musaev
authors: Huw M L
authors: HM
authors: Davies
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D003521:Cyclopropanes / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003521:Cyclopropanes; D006842:Hydrocarbons, Brominated; D008024:Ligands; D009942:Organometallic Compounds; C570725:tetrakis-(R)-(1-(4-bromophenyl)-2,2-diphenylcyclopropanecarboxylate); D012238:Rhodium