Benzonitriles positions

The reaction of arylnitrile oxides with 1,1-diphenylallenes gave a mixture of 4-methylene-2-isoxazolines (Scheme 106) with major attack at the C(2)—C(3) double bond (74JCS(P2)l30l, 76CSC67, 76CSC71, 72JCS(P2)1914) and not a mixture of the 4- and 5-methylene compounds. 1-Phenoxyallene and benzonitrile oxide produced a mixture of positional isomers and a spiro compound (Scheme 107) (79JOC2796). 

Electrostatic potential map for benzonitrile shows negatively-charged regions in red and positively-charged regions (in blue). 

Recently, it was shown that the attack of CN on [FeCp(C6H5Cl)]+ PFortho-position. In the intermediate cyclohexadienyl complex, the CN group migrates to the ipso-carbon, whereas Cl is displaced. The monosubstituted benzonitrile complex is subjected to a second ortho-CN- attack but hydride is not removed spontaneously to give back an arene complex (Scheme XIX). Removal of the hydride is achieved by oxidation using DDQ (2,3-dichloro-... 

In addition to coordination by heteroatoms, the 7r-bond of cyano group also participates the activation of C-H bonds (Equation (14)).14 The ruthenium-catalyzed alkylation of benzonitriles with triethylvinylsilane proceeds at the ortho-position predominantly. 

The metalation of trialkylsilylphosphane and -arsane with the alkaline earth metal bis[bis(trimethylsilyl)amides] of calcium, strontium, and barium yields the mixed phosphanides and phosphanediides as well as arsanides and arsanediides depending on the stoichiometry and the demand of the trialkylsily] substituents according to Scheme 3.6-11. The main feature is the M2E3 bipyramid with the metal atoms in apical positions. These cages are often interconnected via common faces (61, 63, 64, 65, 67, and 69). A substitution of the phosphanide substituents by other Lewis bases such as THF or benzonitrile is not possible for these compounds and, consequently, homoleptic phosphanediides and arsanediides with inner M4E4 heterocubane moieties are so far unknown for M = Ca, Sr, and Ba. In all these cases a further metalation to obtain homoleptic phosphanediides failed. 

The sensitivity of position 2 in 4-chloroquinazoline for nucleophilic addition was also demonstrated in the reaction with lithium piperidide (73RTC460). Whereas in the amination with potassium amide/liquid ammonia no open-chain intermediate could be isolated, with lithium piperi-dide/piperidine the open-chain compound ort/z6>-(piperidinomethy-leneamino)benzonitrile (78,60%) was obtained, in addition to 4-piperidino-quinazoline (80,19%) (Scheme 11.35). The formation of 80 from 78 involves... 

Figure 3. Atomic positions in the hypermolecule of 31 substituted benzonitriles.

Another approach to obtain pure enantiomers of isoxazolines involves the use of chiral acrolein aminals, formed with A.A -substituted diaminodiphenylethanes (194). Thus, with this chiral imidazolidinyl auxiliary in the p-position, and with unsaturated esters serving as the dipolarophile, benzonitrile oxide afforded only one regioisomeric cycloadduct with good stereoselectivity (194) (Scheme 6.40). When the analogous A,A -dimethyl auxiliary was chosen, excellent stereoselectivity was accompanied by poor regioselectivity (194). 

Palladium chloride bis(benzonitrile) reacts with allene probably by an insertion mechanism to produce 7r-2-chloroallylpalladium chloride dimer and products containing two allene units per palladium atom (84). It would appear that the palladium chloride addition to allene occurs both possible ways to one of the double bonds. Addition of the palladium to the terminal position would give a 7r-allyl... 

The positions of the three principal bands (A, B, and C) are listed in Table IX for several complexes. B and C appeared when Ni[P-(C6H5)3]3 was added to a solution of the nitrile (band B). Therefore it is reasonable to assign band B and C> respectively, to the free nitrile and to the nitrile coordinated on the nickel(0). A shift of v (CN) to lower frequency on complexation of benzonitrile to Ni[P(0-o-C6H4CH3)3]3 has been reported recently (20). A further proof that nickel(0) complex is responsible for band C is its disappearance on addition of an aromatic halide. 

E.. .. and on the positive-going sweep, benzonitrile is regenerated here... 

This method is suitable for the preparation of mono- and di-a-substituted /3-ketoesters. Bromoacetates fail in this reaction. Yields with ethyl a-bromopropionate are considerably lower (30-36% with capronitrile) however, ethyl esters are useful for higher-molecular-weight compounds whose sec-alkyl esters are cracked by distillation. With 3-pentyl a-bromopropionate, the yields are slightly higher (53-60% with capronitrile). Both aromatic and aliphatic nitriles are suitable benzonitrile gives yields comparable to those obtained with capronitrile. Alkyl substitution in the a- and /8-positions (cf. Note 4) of aliphatic nitriles lowers the yield to 29% and 38%), respectively 7-substitution has no effect. 

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