Acetonitrile Addition reactions

However, the term saturated is often applied to compounds containing double or triple bonds which do not easily undergo addition reactions. Thus ethanoic acid is termed a saturated carboxylic acid and acetonitrile a saturated nitrile, whereas a Schiff base is considered to be unsaturated. 

Mixing trichlorosilane, acetonitrile and diphenylsulphoxide, carried out at 10°C, detonated. This accident was put down to the exothermic addition reaction of the silicon-hydrogen bond on the carbon-nitrogen triple bond of nitrile. Other interpretations are possible for instance, the effect of traces of hydrogen chloride formed by the hydrolysis of chlorosilane on acetonitrile. 

Ono and coworkers have extended the radical elimination of v/c-dinitro compounds to P-nitro sulfones151 and P-nitro sulfides.138,152 As P-nitro sulfides are readily prepared by the Michael addition of thiols to nitroalkenes, radical elimination of P-nitrosulfides provides a useful method for olefin synthesis. For example, cyclohexanone is converted into allyl alcohol by the reaction shown in Eq. 7.110. Treatment of cyclohexanone with a mixture of nitromethane, PhSH, 35%-HCHO, TMG (0.1 equiv) in acetonitrile gives ahydroxymethylated-P-nitro sulfide in 68% yield, which is converted into the corresponding allyl alcohol in 86% yield by the reaction with Bu3SnH.138 Nitro-aldol and the Michael addition reactions take place sequentially to give the required P-nitro sulfides in one pot. 

Steady-state fluorescence spectra, fluorescence quantum yield (F) and lifetimes (tf) of DTT 15 and DTP 23a were estimated as shown in Table 8. F for DTT is higher than DTP. F for DTP is very small and it was difficult to estimate an accurate fluorescence lifetime by the photon counting method due to weak fluorescence. It is noted that the for DTP depends largely on the solvent and is 7.7 x 10-5 in acetonitrile. This low F value has been attributed to an addition reaction with the solvent. 

Characteristically, for these reactions in anhydrous acetonitrile, at least one additional reaction step is also observed. Whereas the initial solvent exchange step is fast in each case and shows a first-order depen-... 

Extreme cases were reactions of the least stabilized, most reactive carbene (Y = CF3, X = Br) with the more reactive alkene (CH3)2C=C(CH3)2, and the most stabilized, least reactive carbene (Y = CH3O, X = F) with the less reactive alkene (1-hexene). The rate constants, as measured by LFP, were 1.7 x 10 and 5.0 X lO M s, respectively, spanning an interval of 34,000. In agreement with Houk s ideas,the reactions were entropy dominated (A5 —22 to —29e.u.). The AG barriers were 5.0 kcal/mol for the faster reaction and 11 kcal/ mol for the slower reaction, mainly because of entropic contributions the AH components were only —1.6 and +2.5 kcal/mol, respectively. Despite the dominance of entropy in these reactive carbene addition reactions, a kind of de facto enthalpic control operates. The entropies of activation are all very similar, so that in any comparison of the reactivities of alkene pairs (i.e., ferei)> the rate constant ratios reflect differences in AA//t, which ultimately appear in AAG. Thus, car-benic philicity, which is the pattern created by carbenic reactivity, behaves in accord with our qualitative ideas about structure-reactivity relations, as modulated by substiment effects in both the carbene and alkene partners of the addition reactions. " Finally, volumes of activation were measured for the additions of CgHsCCl to (CH3)2C=C(CH3)2 and frani-pentene in both methylcyclohexane and acetonitrile. The measured absolute rate constants increased with increasing pressure Ayf ranged from —10 to —18 cm /mol and were independent of solvent. These results were consistent with an early, and not very polar transition state for the addition reaction. 

The photo-induced addition reaction of 1,4-dibromopiperazine-2,5-dione with several alkenes has been studied (80BCJ219 83BCJ1705 86BCJ479). In acetonitrile, the reaction with cyclohexene occurs by a radical chain mechanism as shown in Scheme 15 (in a sequence of reactions). 

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). 

In the case of electrophilic addition, the reactions of tricyclic dienes 1 with several electrophilic reagents have been investigated.1 7 Interestingly, some of these compounds undergo addition reactions with remarkable syn stereoselectivity. For example, the reaction of dimethyl tricy-clo[4.2.2.02,5]deca-3,9-diene-7,8-dicarboxylate with iodine azide solution, prepared in situ from an excess of sodium azide and iodine monochloride, in acetonitrile at — 5 C provided the. yyn-4-azido-3-iodo derivative 2 (Table 1) in 90% yield.1,2,4,6 The formation of the 5,>,n-4-azido-3-iodo derivative 2 is thought to be the first example of a syn addition of iodine azide to an alkene.1,2 The formation of the syn-product is best explained by the twist strain theory,8 according to which the syn transition structure A is favored over the an/7-coplanar transition structure B.1... 

When the bis(isopropylamino)iodocyclopropenylium iodide is reacted with platinum black in acetonitrile, the reaction takes a different course, affording mainly the trans-bis[bis(diisopropylamino)cyclopropenylidene] diiodoplatinum complex (equation 277)351. A plausible pathway for this reaction involves two consecutive oxidative additions to platinum leading to the hexacoordinated intermediate Ptlv-complex [ -Pr2N)2C3]Ptf4, followed by reductive elimination of I2 to form the product (cf Section VI. A. 1. a). 

Addition reactions of carbon radicals to C—O and C—N multiple bonds are much less-favored than additions to C—C bonds because of the higher ir-bond strengths of the carbon-heteroatom multiple bonds. This reduction in exothermicity (additions to carbonyls can even be endothermic) often reduces the rate below the useful level for bimolecular additions. Thus, acetonitrile and acetone are useful solvents because they are not subject to rapid radical additions. However, entropically favored cyclizations to C—N and C—O bonds are very useful, as are fragmentations (see Chapter 4.2, this volume). 

Aroylcyanides.2 Aroyl cyanides can be prepared by reaction of an aroyl chloride with KCN in acetonitrile. Addition of a trace of water markedly accelerates the rate and improves the yield (by as much as 100%). No other additives show this effect. 

Rate constants (k X 10 9 M-1sec-1) were determined to be 7.0, 3.5, and 1.0 for the enumerated substrates, respectively. The change in kinetics for the three cation radicals with increasing steric hindrance at the (3-carbon is in accordance with the depicted addition reaction. In contrast with that, a reaction of the azide ion with these three cation radicals in acetonitrile proceeds with rate constants that are the same in all three cases ( 3 X 109 M-1sec-1). In acetonitrile, the reaction consists of one-electron transfer from the azide ion to a cation radical. As a result, a neutral styrene and the azidyl radical are formed. The azidyl radical reacts with the excess azide ion, and the addition reaction does not take place ... 

Dinitrobenzofuroxan (DNBF) is known as a superelectrophile due to its high reactivity both as an electrophile and in its pericyclic addition reactions. NMR studies show that reaction with 2-aminothiazole and its 4-methyl derivative yield anionic carbon-bonded adducts such as (11) by reaction at the 5-position, whereas the 4,5-dimethyl derivative reacts via the exocyclic amino group. Kinetic studies of the first two compounds, both in acetonitrile and in 70 30 (v/v) water-DMSO, have been used to assess their carbon nucleophilicities and place them on the Mayr nucleophilicity scale.55 In a related study, the nucleophilic reactivity, in acetonitrile, of a series of indoles with both DNBF and with benzhydryl cations have been compared and used to determine nucleophilicity parameters for the indoles.56... 

Nucleophilic addition reactions of para-substituted benzylamines (XC6H4CH2NH2) to a-phenyl-/9-thiophenylacrylonitriles [Y(C4SH2)CH=C(CN)C6H4Y/] have been studied in acetonitrile at 25.0, 30.0, and 35.0 °C. The reactions apparently take place in a single step in which the C/ -N bond formation and proton transfer to C of a-phenyl-/3-thiophenyl acrylonitriles occur concurrently with a four-membered cyclic transition structure. These mechanistic conclusions were deduced from the following ... 

The treatment of dihydropyridines with diaryldisulfane in boiling acetonitrile also yields products of an addition reaction like 308 in a mixture with arylsulfides [336]. 

A wide range of solvents can be used. Most appropriate are acetonitrile, dichloro-methane and toluene, but alcohols and water may also be employed. In those cases, depending on the substrates, an additional reaction such as cleavage of formed lactones or acetals might occur. 

Previously, Ohashi and his co-workers reported the photosubstitution of 1,2,4,5-tetracyanobenzene (TCNB) with toluene via the excitation of the charge-transfer complex between TCNB and toluene [409], The formation of substitution product is explained by the proton transfer from the radical cation of toluene to the radical anion of TCNB followed by the radical coupling and the dehydrocyanation. This type of photosubstitution has been well investigated and a variety of examples are reported. Arnold reported the photoreaction of p-dicyanobenzene (p-DCB) with 2,3-dimethyl-2-butene in the presence of phenanthrene in acetonitrile to give l-(4-cyanophenyl)-2,3-dimethyl-2-butene and 3-(4-cyanophenyl)-2,3-dimethyl-l-butene [410,411], The addition of methanol into this reaction system affords a methanol-incorporated product. This photoreaction was named the photo-NO-CAS reaction (photochemical nucleophile-olefin combination, aromatic substitution) by Arnold. However, a large number of nucleophile-incorporated photoreactions have been reported as three-component addition reactions via photoinduced electron transfer [19,40,113,114,201,410-425], Some examples are shown in Scheme 120. 

Mo(CO)6 was also used to catalyze Kharasch addition reactions of tetrachloro-methane or trichloroacetates to terminal olefins in acetonitrile (Fig. 38) [218]. A precomplexation like for Cr(CO)6 was not necessary. The ligand exchange... 

Tretyakov and Filimonov (219) describe a coordinative interaction between benzonitrile and aprotic sites on magnesium oxide, and Zecchina et al. (256) came to the same conclusion for the adsorption of propionitrile, benzonitrile, and acrylonitrile on a chromia-silica catalyst. Chapman and Hair (257) observed an additional chemical transformation of benzonitrile on alumina-containing surfaces, which they describe as an oxidation. Knozinger and Krietenbrink (255) have shown that acetonitrile is hydrolyzed on alumina by basic OH- ions, even at temperatures below 100°C. This reaction may be described as shown in Scheme 2. The surface acetamide (V) is subsequently transformed into a surface acetate at higher temperatures. Additional reactions on alumina are a dissociative adsorption and polymerizations (255) analogous to those observed for hydrogen cyanide by Low and Ramamurthy (258), and a dissociative adsorption. Thus, acetonitrile must certainly be refused as a probe molecule and specific poison. 

Diorgano tellurium oxides are reduced by hydrazine hydrate to diorgano tellurium compounds. The diorgano tellurium oxides are obtained as the primary products of the reactions of arenetellurinyl acetate or trifluoroacetates with olefins in chloroform, 1,2-dichloroethane, or acetonitrile as reaction media. When the olefin has a hydroxyl group in a f -, y-, or fi-position to the double bond, the addition of the tellurium compound to the double bond is followed by cyclization forming oxacycloalkane derivatives1. 

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. 

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