Arylation of amines and alcohols catalyzed by nickel, copper or palladium complexes

Abstract

Abstract The arylation reaction of primary and secondary amines has been investigated using nickel or palladium complexes as catalysts, and bromo- or chloroarenes as arylating agents. Among the complexes tested, the more efficient catalyst is the bis (bipyridyl) nickel (II) bromide, bipy 2 NiBr 2 , which affords for example high yields in the arylation of allylamine with m -bromotrifluoromethylbenzene. The reduction of the haloarene, sometimes observed with the nickel complexes, becomes predominant with palladium catalysts whatever the complex used. For the arylation of primary or secondary alcohols, the same nickel complex, bipy 2 NiBr 2 (in presence of base, particularly KHCO 3 ), prove to be the more active catalyst, even in regard to various usual copper catalysts. The reaction affords good yields in alkylarylethers, under relatively mild conditions. An attempted mechanism, based on a catalytic cycle with a nickel(I) active species, is formulated on account of earlier mechanistic investigations described in the literature. Lastly, an unexpected aminolysis of nitriles catalyzed by the nickel (II) bromide, which affords an interesting new way to amides, is described.