Preparation of a cobalt-containing P,N-bidentate ligand ligated palladium complex: Its applications in amination and Suzuki cross-coupling reactions

A cobalt-containing P,N-ligand, alkyne-bridged dicobalt phosphine [(mu-PPh2CH2PPh2)Co-2(CO)(4) (mu,eta-Me2NCH2C = CP(Cy)(2))] (4c), was prepared from the reaction of Me2NCH2C = CPR2 (2c) with a dppm-bridged dicobalt complex [Co-2(CO)(6)(mu-P,P-PPh2CH2PPh2)] (3). Further reaction of 4c with Pd(COD)Cl-2 gave a 4c-chelated palladium dichloride complex (mu-PPh2CH2PPh2)Co-2(CO)(4) (mu,eta-Cy2PC = CCH2NMe2)- PdCl2 (5c). Compound 5c was characterized by spectroscopic methods and crystal structure of 5c was determined by single-crystal X-ray diffraction techniques. It shows that 4c is an authentic cobalt-containing P,N-bidentate ligand. Amination and Suzuki reactions employing either a 4c/palladium salt system or an isolated 5c as the catalytic precursor led to satisfactory results. (c) 2009 Elsevier B.V. All rights reserved.