Diphosphinite PCP-pincer pro-ligands anchored by a meta-terphenyl backbone were synthesized. These pro-ligands, [2,6-(2-Ph 2POC 6H 4) 2C 6H 3X] (3a X = I, 3b X = Br) and [2,6-(2-'Pr 2POC 6H 4) 2C 6H 3X] (4a X = I, 4b X = Br) upon reaction with Pd 2(dba)3 yield PCP palladium pincer complexes [2,6-(2-Ph 2POC 6H 4) 2C 6H 3PdX] (5a X = I, 5b X = Br) and [2,6-(2-'Pr 2POC 6H 4) 2C 6H 3PdX] (6a X = 1, 6b X = Br). The structures of 5a-b and 6a-b were determined by single crystal X-ray diffraction analyses. Complexes 5b and 6b were evaluated for their efficacy in promoting catalytic Suzuki-Miyaura CC coupling reactions. A variety of aryl bromides efficiently underwent CC coupling reactions with p-tolylboronic acid with high yields in the presence of either 5b or 6b. Compound 6b also proved to be a very active pro-catalyst for the coupling of aryl chlorides with p-tolylboronic acid. Excellent to good yields (in some cases greater than 90%) were achieved even with electron rich or sterically hindered aryl chlorides.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry