Organometallic compounds reactions with nitriles

The most general synthetic route to ketones uses the reaction of carboxylic acids (or their derivatives) or nitriles with organometallic compounds (M.J. Jorgenson, 1970). Lithium car-boxylates react with organolithium compounds to give stable gem-diolates, which are decom-... 

Nitriles are similar in some respects to carboxylic acids and are prepared either by SN2 reaction of an alkyl halide with cyanide ion or by dehydration of an amide. Nitriles undergo nucleophilic addition to the polar C=N bond in the same way that carbonyl compounds do. The most important reactions of nitriles are their hydrolysis to carboxylic acids, reduction to primary amines, and reaction with organometallic reagents to yield ketones. 

The same electrochemical process was also used for the coupling between aldehydes or ketones and activated alkyl halides such as a-chloroesters, -nitriles, and -ketones as well as aya-dichloroesters.334 Electroanalytical studies have shown initial electroreduction of Fe(n) to Fe(i) and subsequent formation of an iron organometallic intermediate (e.g., a 7t-allyliron complex in Equation (27)) before reaction with the corresponding carbonyl compounds.335... 

In this book we are not concerned with organometallic reactivity of compounds containing M-C bonds, and so to all intents and purposes this section is about the reactions of nitriles or cyanides with nucleophiles. Reactions of co-ordinated alkynes are adequately discussed elsewhere. 

The aryl unit of these species shows carbanionic properties and consequently reacts with electrophiles. As a result, these organometallic reagents are of great value for the synthesis of a wide range of aromatic compounds. In particular, reaction with carbon electrophiles such as carbonyl compounds and nitriles results in the formation of a new carbon-carbon bond. 

Many organometallic zinc species are too unreactive to undergo cross-coupling reactions with carbon nucleophiles. This general statement cannot be applied to allylic organometallic species which smoothly react with several electrophiles, such as carbonyl compounds [35,36], nitriles [37,38], or triple bonds [39] (Scheme 9-10). 

Complexes of organotin with amidines have been found to be excellent catalysts for the preparation of polyurethane foams, which do not have the disadvantage of any amine odor and, in addition, delayed onset of the isocyanate-hydroxyl reaction An example of a mercapto-delayed organotin catalyst is 2,2,4,4-tetrakis(alkyl)- l,3,2,4-dithia-stannetane.55 Amine salts of amino acids, tertiary amino acids, and tertiary amino acid-nitrile compositions, have been found to be effective as delayed action catalysts for polyurethane synthesis. They are particularly effective when used in combination with an organometallic compound, such as an organotin. ... 

The reaction of 1-boraadamantane (5) with aromatic nitriles also proceeds according to the organometallic synthesis scheme. As in the reaction with carbonyl compounds, the initially formed complexes (100) (Scheme 37) transform to dimers of 5-aryl-4-aza-3-bora-l,l-bihomoadamantane-4-enes (101) when heated higher than 200 °C <84JOM(260)25>. Compounds (101) are stable in the air and do not react with alcohols however, they can be cleaved with 8-hydroxyquinoline to give bicyclic compounds (102) <84jom(260)25>. 

---