Reactive & Functional Polymers, Vol.29, No.3, 151-157, 1996
Facile hydrodebromination of organic bromides with dihydrogen and polymer-anchored palladium catalyst under mild conditions
The hydrodebromination of organic bromides with dihydrogen and the soluble polymer-anchored palladium catalyst PVP-PdCl2 (PVP = poly(N-vinyl-2-pyrrolidone)) was effectively carried out in ethanol by using sodium acetate as the base and at 60 degrees C and atmospheric pressure. This catalyst exhibited very high catalytic activity, selectivity and efficiency for the hydrodebromination of aromatic bromides and some aliphatic bromides. The selectivities of the products for the hydrodebromination of benzyl bromide and omega-bromoacetophenone were obviously increased by means of the soluble polymer-anchored bimetallic catalyst PVP-PdCl2-RuCl3. It was found that the poisoning effect of halogen ions can lead to a decrease of the catalytic activity and deactivation of the catalyst in some cases. Two types of neighboring group participation are proposed to account for the strong substituent effect of the ortho- and meta-substituted aromatic bromides in their hydrodebromination.