Tetra-n-butylammonium cyanide

Nitrobenzenes react with potassium cyanide in the presence of cetyltrimethylammo-nium bromide to yield benzonitriles [71], The reaction also requires the presence of chloro substituents on the ring and at least two nitro groups (Table 2.9). Diazosulphides, ArN=NSPh, are converted into the benzonitriles, ArCN, by a photochemically induced SRN1 reaction with tetra-n-butylammonium cyanide [72, 73], Yields vary from <20% to >70%. Photocyanation of aromatic hydrocarbons has been achieved using tetra-n-butylammonium cyanide in acetonitrile or dichloromethane [74, 75]. 

The direct formation of A-substituted phthalimides from phthalic anhydride and alkyl azides, via the intermediate RN=PPh, compound, is catalysed by the presence of tetra-n-butylammonium cyanide [34],... 

Acetone cyanhydrin has been used as a convenient source of cyanide ion for the preparation of alkyl cyanides (6.1.1.E) [21]. Moderate yields (50-77%) have been achieved using tetra-n-butylammonium cyanide or hydroxide as the base. 

Tetra-n-butylammonium cyanide is a better catalyst for benzoin condensation reactions than is sodium cyanide, and >70% yields are obtained under mild conditions [63, 64] tetra-ethylammonium cyanide is less effective. Polymer-supported ammonium catalysts have also been used to promote the benzoin reaction and, although yields are only moderate (40-60%), the convenience of removal of the catalyst is an advantage. Use of chiral ammonium groups produces an enantiomeric excess of chiral products from the condensation of benzaldehyde, but furfural tends to produce a racemate [65]. 

Reductive metallation of aldehydes (but not ketones) by tri-n-butyl-(trimethyisilyl)stannane to yield a-hydroxystannanes is catalysed by tetra-n-butylammonium cyanide [15]. Other phase-transfer catalysts are not as effective and solvents, other than tetrahydrofuran, generally give poorer conversions. Use of a chiral catalyst induced 24% ee with 3-phenylpropanal. 

The danger of formation of sugar pyridinium salts when using tri-fluoroacetic anhydride in pyridine may be avoided by using 2,6-di-t-butyl-4-methylpyridine. Reaction of carbohydrate triflates with cyanide ion allows inversion at the hydroxy carrying centre either sodium cyanide or tetra-n-butylammonium cyanide were used in a one-... 

Examples of the Michael-type addition of carbanions, derived from activated methylene compounds, with electron-deficient alkenes under phase-transfer catalytic conditions have been reported [e.g. 1-17] (Table 6.16). Although the basic conditions are normally provided by sodium hydroxide or potassium carbonate, fluoride and cyanide salts have also been used [e.g. 1, 12-14]. Soliddiquid two-phase systems, with or without added organic solvent [e.g. 15-18] and polymer-supported catalysts [11] have been employed, as well as normal liquiddiquid conditions. The micellar ammonium catalysts have also been used, e.g. for the condensation of p-dicarbonyl compounds with but-3-en-2-one [19], and they are reported to be superior to tetra-n-butylammonium bromide at low base concentrations. 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

One of the oldest techniques for overcoming these problems is the use of biphasic water/organic solvent systems using phase-transfer methods. In 1951, Jarrouse found that the reaction of water-soluble sodium cyanide with water-insoluble, but organic solvent-soluble 1-chlorooctane is dramatically enhanced by adding a catalytic amount of tetra-n-butylammonium chloride [878], This technique was further developed by Makosza et al. [879], Starks et al. [880], and others, and has become known as liquid-liquid phase-transfer catalysis (PTC) for reviews, see references [656-658, 879-882], The mechanism of this method is shown in Fig. 5-18 for the nucleophilic displacement reaction of a haloalkane with sodium cyanide in the presence of a quaternary ammonium chloride as FT catalyst. 

Thallium(I) cyanide was introduced by Taylor and McKillop as a reagent. Aromatic and heteroaromatic acyl cyanides are produced in go yield, whereas aliphatic acid halides lead under these conditions mainly to dimerization products. 18-Crown-6 is a good catalyst for the preparation of cyanoformate in methylene chloride with potassium cyanide and chloroformates. Similarly, tetraethylammonium cyanide gives cyanoformates in high yield under very mild conditions. Aroyl cyanides are generated easily by phase transfer catalysis with tetra-n-butylammonium bromide. Tri- -butyltin cyanide proved successful only with aromatic acid halides, leading to dimerization products with aliphatic compounds. ... 

Preparative Method aqueous Hydrofluoric Acid is passed through an Amberlite IRA 410 OH column, followed by an aqueous solution of Tetrabutylammonium Bromide. After the resin is washed with water, the combined water fractions are repeatedly evaporated until no water is present. Tetrahutylammonium fluoride is collected as an oil in quantitative 3neld. TBAF-a H20 aqueous hydrofluoric acid is passed through an Amberlite IRA 410 OH column, followed by an aqueous solution of tetra- -butylammonium bromide. After the resin is washed with water, the combined water Iractions are repeatedly evaporated until no water is present. Tetrabutylanunonium fluoride is collected as an oil in quantitative yield. The hydrofluoric acid method has been described most recently by Kumar. TBAFanh under nitrogen, hexafluorobenzene is added to a cold (—50 °C) THF solution of tetra-n-butylanunonium cyanide. The highly colored solution is stirred for 4 h at —15 °C, cooled to —60 °C, and filtered. The resulting colorless solid is washed with cold THF and the residual solvent is removed in vacuo to yield anhydrous TBAF (60%). ... 

In 1951, Jarrouse found that the reaction of aqueous-soluble sodium cyanide (NaCN) and organic-soluble 1-chlorooctane (I-C8H17CI) is dramatically enhanced by adding a small amount of quaternary ammonium salt (R4N X , or Q X", Q R4N ). The reaction is almost complete and a 95% conversion is obtained within two hours when a catalytic amount of tetra-n-butylammonium chloride ((C4H9)4N C1 , or Q CL, Q (C4H9)4N ") is added. The mechanism of the reaction of sodium cyanide and 1-chlorooctane in organic solvent/water two-phase medium is expressed as... 

Nickel cyanide I sodium hydroxide tetra-n-butylammonium bromide <-... 

The palladium-catalyzed domino assembly of norbornene (65), the ds-alkenyl iodide 66, and a terminal alkyne or cyanide reported by Torii, Okumoto et al. [315] provides an example for a sequence of oxidative addition, intermolecular double bond insertion, and interception of a copper acetylide or potassium cyanide. These reactions with acetylenes have been performed in good yields in the presence of diethylamine, tetra-n-butylammonium chloride, and catalytic amounts of palladium acetate, triphenylphosphine, and copper] I) iodide. Remarkably, they are characterized by complete inversion of the cis configuration of the alkenyl iodide and a high degree of discrimination for the enantiotopic ends of the double bond in norbornene. To account for that, intermediate formation of a cyclopropylcarbinyl-palladium species by a 3-exo-trig cyclization in 67 and subsequent cycloreversion to a new homoallylpalladium intermediate as the direct precursor to 68 and 69 has been assumed. Thus, the products 68 and 69 are formed virtually with complete stereoselectivity (Scheme 8.17). 

General Synthesis and Reactions.—Linear primary alcohols with at least seven carbon atoms are transformed into esters in high yield using copper oxide at temperatures above 170 C in the liquid phase. RusfCO) catalyses the conversion of an aldehyde, or an alcohol with the same number of carbon atoms, into an ester in the presence of diphenylacetylene. " The carbonylation of organic halides in the presence of cyclic ethers is catalysed by PhPdI(PPh3)2 , it provides a synthesis of halohydrin esters in reasonable yield. Cyanohydrin esters have been synthesized by the sodium borohydride reduction of acyl cyanides in the presence of tetra-n-butylammonium bromide. ... 

Acyl cyanides are the starting materials for a new synthesis of cyanohydrin esters via a two-phase reduction with sodium borohydride in the presence of tetra-n-butylammonium bromide. 

Many investigators have studied substitution at iron(II)-diimine complexes in binary aqueous mixed solvents and other investigators in aqueous salt solutions. Some years ago the results of addition of salts and a cosolvent were assessed, for [Fe(5N02phen)3] in water, t-butyl alcohol, acetone, dimethyl sulfoxide, and acetonitrile mixtures containing added potassium bromide or tetra-n-butylammonium bromide. " Now the effects of added chloride, thiocyanate, and perchlorate on dissociation and racemization rates of [Fe(phen)3] in water-methanol mixtures have been established. The main explanation is in terms of increasing formation of ion pairs as the methanol content of the medium increases, but it is somewhat spoiled by the (unnecessary) assumption of a mechanism involving interchange within the ion pairs. Kip values (molar scale) of 11,18, and 25 were estimated for perchlorate, chloride, and thiocyanate in 80% (volume) methanol at 298.2 K. These values may be compared with values of 20, 7, and 4 for association between [Fe(phen)3] and iodide, " [Fe(bipy)3] and iodide, " and [Fe(phen)3] and cyanide " " in aqueous solution (at 298.2,... 

Diethylamine acetate Pyridinium salt Tetramethylammonium acetate, Tetraethyl-ammonium Tetra-butylammonium -Bis(tetra-n-butyl-ammoniumjoxalate Tetrabutylammonium cyanide... 

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