Benzonitriles, synthesis from aryl

TABLE 1.14. MICROWAVE ASSISTED SYNTHESIS OF 2-PHENYL-4-SUBSTITUTED OXAZOLES AND 4,5-DISUBSTITUTED 2-PHENYLOXAZOLES FROM ARYL KETONES, BENZONITRILE, AND MERCURY(II)TOSYLATE ... 

Aryl, heteroaryl, and alkenyl cyanides are prepared by the reaction of halides[656-658] or triflates[659,660] with KCN or LiCN in DMF, HMPA, and THF. Addition of crown ethers[661] and alumina[662] promotes efficient aryl and alkenyl cyanation. lodobenzene is converted into benzonitrile (794) by the reaction of trimethylsiiyl cyanide in EtiN as a solvent. No reaction takes place with aryl bromides and chlorides[663]. The reaction was employed in an estradiol synthesis. The 3-hydroxy group in 796 was derived from the iodide 795 by converting it into a cyano group[664]. 

In this context it is interesting to note that benzonitrile, Ph—C=N, trimerizes to a triazine on a Raney nickel surface. It was assumed that Jt-bonded nitriles were involved in the reaction mechanism.10 This reaction resembles the well-known template synthesis of phthalocyanine complexes from phthalodinitrile. Formation of linear polymers [—C(R)—N—] occurs on heating aryl or alkyl cyanides with metal halides.11... 

A very few examples of the use of aryl-tin,21 -lead,21 -lithium43 and -magnesium21143,44 derivatives as the source of the aryl group in vinyl substitutions have been reported. Tin derivatives have been used with palladium dichloride bis(benzonitrile) and a copper(II) chloride reoxidant in a regioselective synthesis of oxygen heterocycles from unsaturated alcohols.43... 

Nucleophilic substitution of aryl halogen atoms requires significant energy input. Thus, in the Dow process for the synthesis of phenol from chlorobenzene, the chlorine atom is only successfully hydrolysed by aqueous sodium hydroxide at 300 °C under pressure. Displacement by ammonia is achieved at 200 °C over copper(I) oxide and conversion to benzonitrile occurs using copper(I) cyanide in boiling dimethylfor-mamide, HCONMe. ... 

A similar beneficial effect of 1,1-diphenylethylene on the yields of arylation products was later observed in the synthesis of benzonitrile derivatives by reaction of diaryliodonium salts with potassium cyanide and in the reaction of diaryliodonium salts with the sodium salt of nitroalkanes. 7 In the latter case, the reaction was therefore considered to result from intermediate inner-sphere radicals. Some years later. Barton et al. showed that 1,1-diphenylethylene acts as an efficient inhibitor of the radical chain process in the reaction of enolates with diaryliodonium salts. They concluded that the arylation products arose from a non-radical process. 

MILLER-SNYDER Aryl Cyanide Synthesis Synthesis of benzonitriles from aldehydes via oxime ethers in the presence of p-nitrobenzonitrile. Formation of p-cyanophenol fron p-nitrobenzaldoxime and p-nitrobenzonitrile (used as a sometimes recyclable chain carrier) (see 1st edition). 

Mondal" described a one-step synthesis of texamine 1173 from benzonitrile and a-diazo-(3, 4 -methylenedioxy)acetophenone using InCla. This approach is similar to Fukushima and Ibata s earlier synthesis of 2-aryl-5-phenyloxazoles (Scheme 1.37). 

Nickel catalyzed O-H additions to imsaturated systems are limited to the hydration reactions of nitriles for the synthesis of amides. These reactions have been widely studied by Prof. J. J. Garcia and his research group and their results recently reviewed [60]. They reported the isolation and characterization of Ni(0) complexes of type [(dippe)Ni(ri -NCR], R = aryl, heteroaryl or alkyl, derived from the reductive interaction of [(dippe)NiH]2 with organic cyanides. The catalytic and synthetic utility of these complexes was demonstrated first in the catalytic hydration of benzonitrile and acetonitrile [61] and then extended to dicyanobenzenes [62], to mono- and dicyanoalkanes [63] and finally to cyanopyridines [64]. 

---