Aromatic amines reductive dehalogenation

Dehalogenation of aromatic amines using catalytic hydrogenolysis takes place easily, usually without the reduction of C=C, COO, C=N, and N02 groups.454,455 The hydrogenolysis of 5-bromo-3-(l-methyl-2-pyrrolidinyl)pyri-dine (38) on Pd/C in EtOH produces nicotine hydrobromide (39) (Scheme... 

Aryl and alkyl hydroxylations, epoxide formation, oxidative dealkylation of heteroatoms, reduction, dehalogenation, desulfuration, deamination, aryl N-oxygenation, oxidation of sulfur Oxidation of nucleophilic nitrogen and sulfur, oxidative desulfurization Oxidation of aromatic hydrocarbons, phenols, amines, and sulfides oxidative dealkylation, reduction of N-oxides Alcohol oxidation reduction of ketones Oxidative deamination... 

The synthetic potential of reductions by formate has been extended considerably by the use of ammonium formate with transition metal catalysts like palladium and rhodium. This forms a safe alternative to use of hydrogen. In this fashion it is possible to reduce hydrazones to hydrazines, azides and nitro groups to amines, to dehalogenate chloro-substituted aromatics, and to carry out various reductive removals of functional groups. For example, phenol triflates are selectively deoxygenated to the aromatic derivatives using triethylammonium formate as reductant and a palladium catalyst. - These recent af li-cations have been reviewed. 

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