Primary organometallic reagent

The dialkylzinc additions catalyzed by N,N-di-n-alkylnorephedrines (most typically DBNE) are not limited to primary organometallic reagents. Diisopropylzinc (with a secondary alkyl substituent) adds to benzaldehyde in the presence of a catalytic amount of DBNE to afford the corresponding alcohol with high ee (entry 4). The reaction of diisopropylzinc in the presence of other types of catalysts may result in the reduction of aldehydes. 

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. 

Amines are nucleophilic and easily oxidized. Primary and secondary amino groups are also sufficiently acidic that they are deprotonated by many organometallic reagents. If these types of reactivity are problematic, the amino group must be protected. The... 

The ring strain inherent in species XV increases its propensity for polymerization. A substantial number of organo-halogenocyclophosphazenes have now been polymerized (7-17). After polymerization, the halogen atoms can be replaced by treatment with alkoxides, aryloxides, primary or secondary amines, or organometallic reagents. 

The homogeneous catalytic reaction occurs in the multi-component liquid phase P. The chemical constituents of the liquid phase include H, e", atoms, ions, and molecules etc. which are dissolved/solvated in one or more molecular or ionic solvents. Primary examples of the ions and molecules present are the dissolved organic and organometallic reagents, intermediates and products. By definition, all the molecular and ionic species involved directly in the homogeneous catalysis are soluble in this liquid phase P. The set of all dissolved species in the phase will be denoted by Eq. (3). 

Primary and tertiary alcohols are obtained conveniently from esters by the reduction of LiAlH4 and two molar equivalents of organometallic reagents (R MgX or R Li), respectively (see Sections 5.7.22 and 5.5.5). A less powerful reducing agent, diisobutylaluminium hydride (DIBAH), reduce an ester to an aldehyde (see Section 5.7.22). 

Addition of organometallic reagent to formaldehyde preparation of primary alcohols... 

The same group2 now finds that a zinc/copper couple prepared by sonication of Zn and Cul in ethanol/H20 (9 1) permits conjugate addition of alkyl halides to enones and enals. The order of reactivity is RI > RBr and tert > sec primary. THF/H20 or Py/HzO or even pure water can be used as solvent. This reaction can hardly involve a classical organometallic reagent, but probably involves an alkyl radical. 

Amination. The carbanions of organometallic reagents react with 1 to give primary amines in moderate yield. Yields are higher in the case of stabilized carbanions.2 The reagent also aminates N-, P-, and S-nucleophiles.1,3 Examples ... 

The reaction of an organometallic reagent with formaldehyde produces a primary alcohol ... 

Monoalkylation of primary amines. A two-step sequence for this reaction involves conversion of the amine to the N-(cyanomethyl)amine (2) by reaction with chloroaceto-nitrile or with formaldehyde and KCN. Reaction of 2 with an organolithium or a Grignard reagent generates an unstable formaldehyde imint (a) that reacts with a second equivalent of the organometallic reagent to form a secondary amine (3). 

Most of the early mechanistic studies that focused on the S ,j2 versus 8 2 nucleophilic substitution by an organometallic reagent were made with allylic halides. In the late 1940s, Wilson [7] showed that phenylmagnesium bromide reacted with a- and y-methylallyl chlorides 1 and 2, respectively, to afford a nearly identical mixture of primary and secondary substituted products 3 and 4, respectively, in a 75 25 ratio [Eq. (1)]. 

The addition of organometallic reagents to 5-aiyl sulfenimines (193) yields, upon aqueous work-up, substituted primary amines (195). The scope of these additions has not been extensively explored, largely because of the difficulties encountered in sulfenimine preparation. Recently, the generation of sulfenimines from N.N-bis(trimethylsilyl)sulfenamides and aldehydes or ketones has provided a more convenient access to these molecules. ... 

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