Anion acetonitrile

Draw a resonance structure of the acetonitrile anion, - CH2C=K, and account for the acidity of nitriles. 

The reaction of 2-isothiocyanato benzonitrile with aryl acetonitrile anions was used to prepare quinazoline thione derivatives 53 <06S3067>. 

ReOCU reacts with PhNCO to give the rhenium(VI) compound [Re(NPh)Cl4] which forms adducts with donor solvents such as TFIF or acetonitrile. Anionic [Re(NPti)Cl5] is obtained when [Re(NPh)Cl4] is treated with [Mc4N]Cl. Two other approaches to rhenium(VI) arylimido compounds include an azo splitting reaction starting from 2-(arylazo)pyridines and the oxidation of rhenium(V) imides by nitric acid. ... 

The balance between anion activation and cation inhibition of addition reactions to carbonyl groups is exemplified by the reaction of acetonitrile anion with benzaldehyde (Scheme 7). When the cation is Li+, addition of [2.1.1]cryptand (15b) markedly decreases the reaction rate suggesting cation inhibition is dominant. When M = K+, addition of [2.2.2]cryptand (15d) increases the rate by, presumably, a predominant anion activation. Finally when M = Na+, the two effects cancel out and the reaction rate is unaffected by [2.2.1]cryptand (15c) addition (80PAC2303,81TL1685). 

The main feature of carbanions derived from nitriles lies in the dependence on the aromatic substrate involved thus, two different outcomes of the substitution reaction are possible formation of the substitution compound by ET to the substrate from the radical anion intermediate 7, formed by coupling of phenyl radicals and acetonitrile anion, or formation of products from elimination of the cyano group as is the case with phenyl halides [31,32] (Sch. 3). The same reactivity pattern is found with halothiophenes [33]. 

An improved electrochemical synthesis of chiral oxazolidin-2-ones from 1,2-aminoalcohols was achieved by reaction with C02 and electrogenerated acetonitrile anion <02TL5863>. The reaction of A-protected amino acids with paraformaldehyde was greatly accelerated by microwave irradiation <02TL9461>. Oxazolidin-2-ones were synthesised by sulfur assisted thiocarbonylation of 2-aminoethanols with carbon monoxide and subsequent oxidative cyclisation with molecular oxygen <02T7805>. 

As shown in Appendix 1, the pAia value for methane is approximately 50-75, and the pAia value for acetonitrile is approximately 25. Thus, the methyl anion is more reactive than the acetonitrile anion and is therefore the better nucleophile. 

These mixed structures have been employed in asymmetric nucleophilic addition reactions. The asymmetric addition of acetonitrile anion to benzaldehyde gives access to synthetically important chiral hydroxy nitriles. 

In S,(N1 reactions implying aryl radicals and acetonitrile anions, the phenyl-acetonitrile radical anionic intermediate undergoes bond rupture showing that in this case a a radical anion is probably formed [110],... 

Reaction of an a-(phenylthio)nitrile with base, such as LDA, followed by an aldehyde or a ketone gives a 1,2-addition product in good yield, while the use of a, -unsaturated aldehy s and ketones usually leads to the 1,4-addition product. Conjugate addition of the a-(phenylthio)acetonitrile anions to 2-methyl- or 2-phenyl-2-cyclohexenones or 2-methyl-2-cyclopentenones, followed by acid quenching under kinetic control, leads to different ratios of cis and rr[Pg.561]

CH2—The anions of 2-substituted-l,3-benzodithioles (34) are readily prepared and are useful acyl carbanion equivalents. N,iV-Diethylamino-acetonitrile anion, EtaNCHCN, has been used as a latent formaldehyde anion. Acetals of /8-diphenylphosphinoyl-ketones (35) (available by five different routes) act as equivalents of homoenolate anions [CH(R )CH(R )COR ] on... 

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