Pd(OAc)₂ Catalyzed Dehalogenation Of Aryl Halides In PEG

The dehalogenation of aryl halides represents an important chemical transformation in organic synthesis and environment remediation. In this thesis, A convenient and efficient catalytic aryl dehalogenation protocol has been developed using a palladium/PEG/pyridine/base system. the results are summarized below.Here we proposed a novel reaction methods employing polyethyleneglycol (PEG) as the reaction media for dehalogenation of aryl halides. PEG was nonvolatile, nontoxic and environmentally benign "green" solvents, comparing to traditional organic reaction solvents. The reaction conditions were mild and avoided the high temperature and the high pressure. Meanwhile, in our systems, we avoided using complex ligands.In this thesis, we first optimized the best reaction conditions, including the chain length of PEGs, bases, temperatures and the mount of the catalysts. Then we studied the hydrodehalogenation of aryl halides in PEG and we found that Pd(OAc)₂-PEG system is an efficient and mild catalytic system for the dehalogenation of aryl iodides and bromides under the optimized conditions. The reaction conditions were mild and the methods were showed highly effective for the dehalogenation of aryl iodines, bromides and polyhalogenated aromatic hydrocarbons in short reaction times.