Substituted cyanides

For carbon substitution, magnesium dialkyls (and biphenyl) and lithium alkyls are effective in the absence of metal halides. Conditions have also been found for cyanide substitution and for hydro-formylation. 

When the cyano (—C=N) group is added and reduced, the resulting amine has an additional carbon atom. In effect, the cyanide substitution-reduction process is like adding —CH2 —NH2. The following synthesis makes 2-phenylethylamine, which we also made by the azide synthesis ... 

Cyano metal complexes are commonly formed by the addition of an excess of cyanide ion (usually as an alkali metal salt) to a transition metal complex in water or a polar organic solvent (equation 1). The completely cyanide-substituted metal complex is usually isolated from these reactions, although one or more steps in the reaction may be relatively slow. In certain cases, cyanide substitution is not complete, resulting in partially substituted cyano metal complexes an example is the addition of CN to Pt alkyl compounds, from which [PtR(CN)3] species are isolated. 

Protonation of a cyanide ligand (see Section 4.3) also can lead to enhanced rates of cyanide substitution, since this... 

Reaction of dimeric, bromo-bridged Co2Br2(NO)4 with NaCN (1 4 mole ratio) in EtOH produces Na[Co(CN)2(NO)2], which may be obtained in pure form by evaporating the solution to dryness, followed by recrystallization from THF-petroleum ether. This compound is also prepared from CoBr(L)(NO) (L = PPh3, SPPhj, SePPhj) with xs NaCN in EtOH at 40-60°C. The same starting materials in a 1 1 mole ratio give instead single bromide-by-cyanide substitution, with formation of Co(CN)L(NO) °. 

Presence of Methyl.—Methyl cyanide, which is the cyanide substitution product of methane, CH3—CN, yields acetic acid when boiled with water. The methyl group must, therefore, undoubtedly be present in acetic acid. This would further make it probable that the other... 

Cyanides Yield Nitriles.—Sandmeyer also applied the principle of his reaction to the preparation of cyanide substitution products, i.e. replacement of the diazo group with cyanogen radical. The reaction is brought about by warming a diazonium salt solution with a solution of cuprous cyanide in potassium cyanide. 

SILACROWN SOLID/LIQUID PHASE TRANSFER CATALYSIS OF POTASSIUM CYANIDE SUBSTITUTIONS... 

Cyanide substitution is an Sj 2 reaction and requires a 1° or 2° carbon with a leaving group. The Grignard reaction is less particular about the type of halide, but is sensitive to, and incompatible with, acidic functional groups and other reactive groups. 

The preparation and properties of a number of cobalt(III)-cyano complexes are given in Table 8. Many reactions involving formation of cobalt(III)-CN bonds are catalyzed by cobalt(II) species. Adamson first proposed that catalysis of cyanide substitution in [CoXCNKj) ] " ions (X = Br , I ) to form [Co(CN)5X] involved the participation of tlie substitutionally labile [Co(CN)5] (Scheme 5). Subsequent mechanistic studies have been interpreted in terms of inner-sphere electron transfer between [Co(CN)5] and [CoX(NH3)5] through bridged [(NC)5CoXCo(NH3)5] intermediates (X = Cl , , NCS , OH ). For a number of other pentaamminecobalt(III) complexes,... 

Photochemical displacement by cyanide has an analogous first step, but the course of subsequent reaction depends on the solvent. In THF, working with a large excess of the carbonyl, the reaction proceeds as for thiocyanate above, but in methylene chloride solution further cyanide substitution occurs to give a mononuclear product ... 

In the 1980s, Hiroyuki Akita and Takeshi Oishi published an enantioselective synthesis of oudemansin A, where a jS-keto-ester is reduced stereoselectively to the jS-hydroxy-ester with Candida albicans. After chromatographic purification from small amounts of diastereomers, the ester is then homologised in a classical reduction and cyanide substitution sequence. The remainder of the synthesis for establishing the acrylate system follows the previously described methodology. [53-55]... 

Nitriles are cyanide-substituted carbo lic acids, which occur naturally and synthetically, and are of the general siructure, R-CN. The naturally occurring nitriles are found in higher plants [94-97], bone oils, insects [98], and microorganisms [99,100] the synthetic ones are used industrially in benzonitrile herbicides [101], as organic solvents and in the synthesis of polymers, plastics [102,103], synthetic fibers, resins, and dye stuffs. 

Sodium cyanide substitutions of benzylic halides in the presence of benzyltriethylammonium chloride thus serves as a typical example.More recently use has been made of supported cyanide reagents, but attempts to do so have often been problematical. 

Cyanide-substituted chromium carbonyl anions have also been prepared. Treatment of Na2[Cr(CO)5] with aqueous sodium or potassium cyanides may lead either to bright yellow Na[Cr(CO)5CN] or colorless Na2[Cr(CO)4(CN)2] depending on the reaction conditions (73) ... 

Selenium.—Much of the work on selenium chemistry has come from the same laboratory that has investigated the cyanide substitutions at the polythionates. A study of nucleophilic substitution by cyanide ion at the dicyanides of sulphur and selenium in acetonitrile leads (in excess cyanide) to the di-iminosuccinonitrile dianion, [(CN)J . ... 

Entering Groups. Rates of reaction of [PtCl4], [PtCl3(OH2)], and [PtCl2(OH2)2] with ethene are all rather similar. Rates and activation parameters for the reaction of a variety of uncharged platinum(ii) complexes with cyanide have been reported. The complexes in question are [PtCl(N02)(NH3)2], [Pt(N02)2(NH3>2], [Pt(CN)a-(en)], and rra s -[Pt(CN)(N02)(NH3)2] cyanide substitution follows the usual rate law [equation (1) above]. The variation of the second-order term with solvent composition for the reaction of [PtCl2(bipy)] with thiourea in aqueous dioxan and in aqueous THE has been discussed in terms of solvent effects on the initial and transition states (see Chapter 5 of this Part). ... 

The synthesis of aldehyde 212 started with an Evans alkylation of the known acylated oxazolidinone 215 with allyl iodide 216 to form the corresponding alkylated product 217 as a single diastereoisomer in 81% yield (Scheme 2.88) [118]. Reductive removal of the chiral auxiliary followed by tosylation of the resulting primary alcohol, cyanide substitution, and reduction with DIBAL... 

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