Palladium-catalyzed hydrodechlorination of ary chlorides and its mechanism

Successful hydrodechlorinations of aryl chlorides were carried out in the presence of palladium catalyst supported by dppf (1,1′-bis(diphenylphosphino)ferrocene) and sodium formate in DMA (N,N-dimethylacetamide). A series of substituted aryl chlorides as substrates were studied to investigate the influence of electronic effects on the reaction. It was found that the substrates with electron-donating groups are more active than those with electron-withdrawing groups. A proposed mechanism of hydrodechlorination via decarboxylation and reductive elimination was discussed with the supported of in situ IR data. It is suggested that the decarboxylation is the key step of the reaction. This inference of the mechanism is consistent with the results from the in situ IR experiments.