Bis(dialkylphosphino)ferrocene-Ligated Nickel(II) Precatalysts for Suzuki–Miyaura Reactions of Aryl Carbonates
| Autor: | Ian L Peczak, Ryan. M. Davis, Megan Mohadjer Beromi, Amira H. Dardir, Hannah M. C. Lant, David Balcells, Brandon Q. Mercado, Gary W. Brudvig, Andrew G Walden, Nilay Hazari, Emily L Barth |
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| Rok vydání: | 2019 |
| Předmět: |
Denticity
010405 organic chemistry Aryl Organic Chemistry Comproportionation 010402 general chemistry 01 natural sciences Medicinal chemistry Oxidative addition Article 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound chemistry Ferrocene Electrophile Physical and Theoretical Chemistry Phosphine |
| Zdroj: | Organometallics |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/acs.organomet.9b00543 |
| Popis: | Aryl carbonates, a common protecting group in synthetic organic chemistry, are potentially valuable electrophiles in cross-coupling reactions. Here, after performing a thorough evaluation of different precatalysts, we demonstrate that (dcypf)Ni(2-ethylphenyl)(Br) (dcypf = 1,1-bis-(dicyclohexylphosphino)ferrocene) is an efficient precatalyst for Suzuki-Miyaura reactions using a variety of aryl carbonates as substrates. Mechanistic studies indicate that (dcypf)Ni(2-ethylphenyl)(Br), which contains a bidentate phosphine that binds in a trans geometry, is an effective precatalyst for these reactions for two reasons: (i) it rapidly forms the Ni(O) active species and (ii) it minimizes comproportionation reactions between the Ni(O) active species and both the unactivated Ni(II) precatalyst and on-cycle Ni(II) complexes to form catalytically inactive Ni(I) species. In contrast, the state of the art precatalyst (dppf)Ni(o-tolyl)(Cl) (dppf = 1,1-bis(diphenylphosphino)ferrocene), which contains a bidentate phosphine that binds in a cis geometry, forms Ni(I) species during activation and is essentially inactive for aryl carbonate couplings. Although the exact reasons on a molecular level why the dcypf system is more active than the dppf system are unclear, our results indicate that in general Ni catalysts supported by the dcypf ligand will give better performance for catalytic reactions involving substrates which undergo relatively slow oxidative addition, such as aryl carbonates. |
| Databáze: | OpenAIRE |
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