Alkylation with organometallic reagents

Copper-catalyzed asymmetric allylic alkylations with organometallic reagents used for small-ring openings, such as epoxides and aziridines, have gained interest. Illustrating... 

C-H Arylation, Alkenylation, Alkylation with Organometallic Reagents 701... 

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. 

Especially in the early steps of the synthesis of a complex molecule, there are plenty of examples in which epoxides are allowed to react with organometallic reagents. In particular, treatment of enantiomerically pure terminal epoxides with alkyl-, alkenyl-, or aryl-Grignard reagents in the presence of catalytic amounts of a copper salt, corresponding cuprates, or metal acetylides via alanate chemistry, provides a general route to optically active substituted alcohols useful as valuable building blocks in complex syntheses. 

The central bond of the l-(arylsulfonyl)bicyclo[1.1.0]butane system behaves like the double bond of a, /i-unsaturated sulfones to give alkyl-substituted cyclobutyl aryl sulfones on treatment with organometallic reagents (equation 20)17. This method has been applied... 

Coupling of alkyl halides with organometallic reagents other than... 

The Reaction of Alkyl Halides with Organometallic Reagents 265 Alkyl-de-halogenation... 

Enediamine 93 undergoes an easy C-alkylation with a,/ -unsaturated ketones under comparable conditions and no cyclocondensation products are observed36. Similar C-alkylations with other electrophilic olefins such as unsaturated lactones, propenonitrile, vinyl sulfoxide, sulfone and phenylphosphonium bromide have been achieved36. All the adducts 135 exist predominantly as the imine form (see Section II.A). Treatment with organometallic reagents transforms the C-alkylated products into... 

Other preparative routes to aluminum alkyls include reaction of aluminum halides with organometallic reagents such as lithium alkyls (Equation (3)). 

Amino, alkoxy, and aryloxy polyphosphazenes are typically prepared by nucleophilic displacement reactions of poly(dihalophosphazenes). Analogous reactions with organometallic reagents, however, result in chain degradation and cross linking rather than in linear, alkyl, or aryl substituted poly(phosphazenes). The thermolysis of appropriate silicon-nitrogen-phosphorus compounds can be used to prepare fully P—C bonded poly(organophosphazenes). The synthesis of two of these materials and their Si—N—P precursors is described here. 

A similar competition between the substitution of the allylic halogen and rearrangement with loss of halogen leading to bicyclic compounds, i.e. 6-alkyl-6-pyrrolidinobicyclo[3.1.0]hexanes was observed upon treatment of a-halogenated cyclic enamines with organometallic reagents (Mg, Li, Cu, hydrides) (Table 2). ° ... 

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