Related Experiment Video
Updated: May 14, 2025
Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Nickel-Catalyzed Regioselective Ring-Opening Hydroarylation of Methylenecyclopropanes
Aishuang Fan1, Xinyi Li1, Jinyang Chen1
1College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
Abstract:
The hydroarylation of methylenecyclopropanes (MCPs) is a challenging process due to the difficulty in controlling regioselectivity and the complex reaction patterns involved. Herein, we report a simple external ligand-free Ni-catalyzed ring-opening hydroarylation of MCPs with high efficiency and unprecedented regioselective arylation as well as broad functional group tolerance by using inexpensive aryl boronic acids as the arylation source. The synthetic utility has been demonstrated for the facile preparation of versatile highly valued products. Mechanistic studies suggest that Ni(II)-H, formed via the oxidative addition of Ni(0) to the proton in the system, might act as a key intermediate.
Related Concept Videos
02:26Base-Catalyzed Ring-Opening of Epoxides
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...