Nucleophilic Displacement Catalyzed by Transition Metal. I. General Consideration of the Cyanation of Aryl Halides Catalyzed by Palladium(II)

Abstract

The displacement reaction of various non-activated aryl halides with cyanide ions was investigated in the presence of palladium salts. Various aryl iodides and bromides were converted into the corresponding aryl cyanides in good yields under mild conditions. The addition of certain substances, such as potassium hydroxide and potassium carbonate, enhanced the catalytic activity. Hexamethylphosphoric triamide, in which potassium cyanide was scarcely soluble, was an outstanding solvent for the reaction. The reduced palladium species was supposed to be the active catalyst.

Copper-catalyzed cyanation of aryl halides with sodium nitroprusside in polyethylene glycol 400 (PEG-400)

“…In summary, we have developed a simple and efficient CuI/PEG-400 catalytic protocol for the cyanation of aryl halides employing Na 2 [Fe(CN) 5 6 ], the nitroprusside reagent shows greater activity. Under the present protocol a variety of aryl iodides and bromides were cyanated smoothly with a wide range of substituent scope in good to excellent yields.…”

“…6 Later, various kinds of CN source were explored，such as palladium-, nickel-and copper-catalyzed methods, using KCN, 7,8 NaCN, 9,10 19 Recently, Beller and co-workers reported Pd-catalyzed cyanation of aryl halides by the use of K 4 Fe(CN) 6 , as a cyanide source, 20 this is non-toxic and cheaper as compared to alkalimetal cyanides such as KCN. Due to its significant advantages, K 4 [Fe(CN) 6 ] has been paid increasing attention as a cyanating agent in cyanation of aryl halides. [21][22][23][24][25][26][27] Among various catalysts for the transition metal-catalyzed cyanation of aryl halides, palladium compounds have been widely investigated, while less expensive copper catalysts received little attention.…”

“…The first case of copper-catalyzed cyanation of aryl halides was reported by Beller and co-workers. 19 Subsequently, many methods of copper-catalyzed cyanation of aryl halides with K 4 Fe(CN) 6 were developed. [24][25][26][27] However, specific ligands and/or organic solvents were needed to obtain high yield.…”

“…[24][25][26][27] However, specific ligands and/or organic solvents were needed to obtain high yield. Very recently, Wang reported an efficient methodology for the cyanation of aryl iodides using copper salt as the catalyst, K 4 [Fe(CN) 6 ] as the cyanide source, and water as the solvent under microwave heating at 140 ºC. 28 Subsequently, Leadbeater reported a similar methodology of cyanation of aryl iodides with K 4 [Fe(CN) 6 ] using water and tetraethylene glycol mixture as solvent.…”

“…Very recently, Wang reported an efficient methodology for the cyanation of aryl iodides using copper salt as the catalyst, K 4 [Fe(CN) 6 ] as the cyanide source, and water as the solvent under microwave heating at 140 ºC. 28 Subsequently, Leadbeater reported a similar methodology of cyanation of aryl iodides with K 4 [Fe(CN) 6 ] using water and tetraethylene glycol mixture as solvent. 29 However, the copper-catalyzed cyanation of aryl-and heteroaryl bromides requires the use of a ten-fold amount of the rather expensive ligand N,N′-dimethylethylenediamine relative to the copper salt.…”