Organolithium reagents nitriles

Addition of Grignard reagents or organolithium reagents to co-halo nitriles leads to 2-substituted cyclic imines. 

Fig. Nitriles react with Grignard reagent or organolithium reagents to produce ketones.

Nitriles A Grignard or organolithium reagent attacks the electrophilic cyano group to form the salt of an imine. Acidic hydrolysis of the salt (in a separate step) gives the imine, which is further hydrolyzed to a ketone (Section 18-9). 

Some imidoyllithiums 52 derived from triphenylmethyl isocyanide (51) dissociate to produce nitriles, which react with an organolithium reagent to give the corresponding imines and, after their hydrolysis, ketones. The intermediate nitrile can be isolated working at —78°C, whereas for the isolation of imines or ketones, after addition of the organolithium, the reaction was allowed to warm to room temperature (Scheme 14)74. The structure of the imidoyllithium intermediate has been assigned by IR spectroscopy... 

Both Grignard and organolithium reagents react with nitriles to form ketones with a new carbon-carbon bond. 

C Reaction of a nitrile with a Grignard or organolithium reagent... 

Reactions of either Grignard or organolithium reagents with most aldehydes, ketones, or esters produce alcohols. Reactions of organolithium reagents with carboxylic acids, or of Grignard reagents with nitriles, produce ketones. 

Discussed in this chapter, for the most part, are documented cases where complexes derived fiom (one or more equivalents of) a Grignard or organolithium reagent, in combination with a copper(I) salt, have been used to add to an aldehyde, ketone, imine, amide or nitrile moiety. In the majority of examples, the key issue is one of stereocontrol. Hence, where available, data within the organocopper manifold versus those for other organometallic reagents are provided for comparison. 

The reaction of cerium reagents with imines and nitriles which possess a-hydrogens has been studied by Wada et al ° Available data indicate that the reagents do not effectively d to these substrates, although the results are better than with alkyllithiums themselves. A modification of the procedure improves the yields of addition products. Thus, addition of the organocerium or organolithium reagent to an... 

Grignard reagents and organolithium reagents add to nitriles to give imines, which are rapidly hydrolyzed to ketones upon addition of water. Only one addition to the C=N triple bond takes place, because a second addition would produce a very high energy RN2 species. 

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