The hydroarylation of alkenes provides access to alkylarenes (example pictured). This reaction can be performed via a reductive coupling of aryl halides and alkenes in the presence of a hydride donor. While there are several protocols for the Markovnikov hydroarylation of alkenes, approaches for the same reaction with anti-Markovnikov selectivity are rare.
Gojko Lalic and colleagues, University of Washington, Seattle, USA, have developed a nickel-catalyzed hydroarylation of alkenes with anti-Markovnikov selectivity. The team used NiCl2(dme) (dme = dimethoxyethane) as the catalyst, polymethylhydrosiloxane (PMHS) as a hydride source, NaOtBu as an additive, and aromatic solvents such as benzene or toluene. These conditions allowed them to react a range of simple alkenes, aryl alkenes, and enol ethers with aryl iodides and aryl bromides.
The desired anti-Markovnikov products were obtained in good to excellent yields. According to the researchers, the reaction’s selectivity is determined by an irreversible hydrometallation step. The developed method complements existing approaches for the hydroarylation of alkenes.
- Nickel-catalyzed anti-Markovnikov hydroarylation of alkenes,
Julia Nguyen, Andrea Chong, Gojko Lalic,
Chem. Sci. 2019.