Nitrile from alkyl halides

Because nitriles can be prepared from alkyl halides by nucleophilic substitution with cyanide ion the overall process RX RC=N RCH2NH2 leads to primary amines that have one more carbon atom than the starting alkyl halide... 

Many other examples of synthetic equivalent groups have been developed. For example, in Chapter 6 we discussed the use of diene and dienophiles with masked functionality in the Diels-Alder reaction. It should be recognized that there is no absolute difference between what is termed a reagent and a synthetic equivalent group. For example, we think of potassium cyanide as a reagent, but the cyanide ion is a nucleophilic equivalent of a carboxy group. This reactivity is evident in the classical preparation of carboxylic acids from alkyl halides via nitrile intermediates. 

As we know, the Grignard reagents and nitriles ean be prepared from alkyl halides (refer Unit 10, Class XII). The above methods... 

Formation of carboxylic acid from alkyl halide using the hydrolysis of a nitrile. 

Functional Group Transformations Functional group transformations help us in the conversion of a functional group to an aldehyde or a ketone without affecting the carbon skeleton of the molecule. Aldehydes can be synthesised by the oxidation of primary alcohols, or by the reduction of esters, acid chlorides, or nitriles. Since nitriles can be obtained from alkyl halides, this a way of adding an aldehyde unit (CHO) to an alkyl halide ... 

Alkylation of metallated a-(dialkylamino)nitriles with alkyl halides, epichlorohydrin, allyl halides or ethyl bromoacetate followed by hydrolysis furnishes an array of ketones in good yield. - For example, reaction of (42) with benzyl chloride leads to the formation of deoxybenzoins. Alkylation of a-(dialkyl-amino)nitriles is also possible if the latter are derived from aliphatic aldehydes. - ... 

It was found that Me3SiCl accelerates the conjugate addition of in situ prepared organosamarium reagents to a,f3-unsaturated carbonyl compounds and nitriles in the presence of HMPA and catalytic amounts of Cu(l) salts (Scheme 296). HMPA is also necessary for the in situ preparation of the organosamarium species from alkyl halide and Sml2.1081... 

X- = CN- From Amberlyst A-26 (Cr) by treatment with aq. KCN Synthesis of nitriles from alkyl and acyl halides ... 

Nitriles can be prepared from alkyl halides and CN (Section 17.3) or from aldehydes and ketones as cyanohydrins (Section 16.9). 

Leadbeater NE, Torenius HM, Tye H (2003) Ionic liquids as reagents and solvents in conjunction with microwave heating rapid synthesis of alkyl halides from alcohols and nitriles from aryl halides. Tetrahedron 59 2253-2258... 

Amines can be prepared from alkyl halides in a two-step process in which the alkyl halide is converted to a nitrile, which then undergoes reduction. 

Alkyl nitriles are also prepared from alkyl halides with sodium cyanide impregnated on alumina and with cyanide ion in the presence of polystyrene-bound n-propyltributylphosphonium bromide, and by hydrocyanation of alkenes and alkynes. ... 

Nitriles are commonly available from aldoximes (aldehydes) and amides (carboxylic acids) by dehydration, from alkyl halides by nucleophilic substitution, and from primary amines by oxidation. It is therefore not surprising that these... 

Amines as Catalysts. Some reports have appeared on the use of amines as catalysts in PTC nucleophilic substitution methods. For example, the preparation of alkyl thiocyanates or nitriles from alkyl bromides in two-phase systems may be assisted by a variety of primary, secondary, or tertiary amines as alternatives to quaternary ions. Efficient catalysis seems to require a sterically unhindered amino group with relatively high basicity (J.e. t-alkyl and aromatic amines are not fully efficient), and a total number of carbon atoms in the amine of greater than six to achieve good phase distribution of the catalysts. A similar study on the alkylation of benzyl methyl ketone reached the same conclusions, and from various observations e.g. that the reaction displayed an induction period at low catalyst concentration) it was postulated that initial alkylation of the amine by the alkylating agent (usually a halide) was essential to provide quaternary ions as the actual catalyst,... 

The new synthesis of aldehydes RCHO from alkyl halides RCHaX outlined in Scheme 16 is reminiscent of the aldehyde- nitrile conversion reported last... 

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