Synthesis, characterization and structural studies of new palladium(II)complex including pyridinium ylides as the homogeneous catalyst for the Suzuki cross-coupling reaction

Pyridinium ylides are important reagents in organic chemistry, especially in the synthesis of naturally occurring products with biological and pharmacological activities. These compounds have been used as reducing agents in coordination chemistry [1]. They can behave as ambidentate ligands, because the carbanion located at the Cα of the ylide is able to donate electron density to a transition metal [2,3]. This work reports the synthesis and catalytic properties of new palladium complex that prepared by reaction of new pyridinium ylides (Y) and PdCl2. The reaction of pyridine with 2-Bromo-2 -acetonaphthone in acetone produces new pyridinium salt (S). The action of K2CO3 on S compound leads to a new type of stable ylide (Y). The reaction of Y with palladium(II) Chloride in dry dichloromethane as a solvent led to the formation of C-coordinated dimeric complex [PdY2Cl2]. The complex was characterized by spectroscopic methods (FT-IR, 13C NMR, 1H NMR). Also, this complex was applied in the Suzuki–Miyaura coupling reactions as an efficient catalyst. Various aryl halides were coupled with aryl boronic acids in DMF, under air atmosphere, in the presence of low-level of the homogeneous catalyst to afford the cross-coupled products in good to excellent yields