The Role of Ligand Transformations on the Performance of Phosphite- and Phosphinite-Based Palladium Catalysts in the Suzuki Reaction
| Autor: | Robin B. Bedford, Simon J. Coles, Andrew R. Cowley, John M. Brown, Michael E. Limmert, Shailesh Ramdeehul, Michael B. Hursthouse, Samantha L. Hazelwood |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | Organometallics. 22:1364-1371 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/om020941f |
| Popis: | The orthometalated complex [{Pd(μ-Cl){κ2-P,C-P(OC6H2-2,4-tBu2)(OC6H3-2,4-tBu2)2}}2] reacts with phenylboronic acid hydrate and K2CO3 in dimethylacetamide to give [Pd{κ2-P,C-μ2-O-P(O)(C6H2-2,4-tBu2)(C6H3-2,4-tBu2)(DMAc)}]. When the reaction is repeated in dimethylformamide 3,3‘,5,5‘-tetra-tert-butyl-2,2‘-biphenol is isolated. Both compounds have been characterized crystallographically. The reaction of palladium dichloride with PiPr2(OC6H4-4-Et) in 2-methoxyethanol followed by recrystallization in the presence of ethanol leads to the formation of trans-[PdCl2{PiPr2(OEt)}2], which was also characterized by crystallography. To determine whether related solvolytic processes have a bearing on catalytic activity, the performance of a range of catalysts with “hydrolyzed” and “nonhydrolyzed” ligands was assessed in the Suzuki coupling of aryl bromides. In some cases it was evident that hydrolysis plays a significant role on the catalytic activity; however, this depends not only on the ligand, but also on the combi... |
| Databáze: | OpenAIRE |
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