Phenylacetylenes acetate

Intermolecular Nucleophilic Substitution with Heteroatom Nucleophiles. A patent issued in 1965 claims substitution for fluoride on fluorobenzene-Cr(CO)3 in dimethyl sulfoxide (DMSO) by a long list of nucleophiles including alkoxides (from simple alcohols, cholesterol, ethylene glycol, pinacol, and dihydroxyacetone), carboxylates, amines, and carbanions (from triphenyhnethane, indene, cyclohexanone, acetone, cyclopentadiene, phenylacetylene, acetic acid, and propiolic acid). In the reaction of methoxide with halobenzene-Cr(CO)3, the fluorobenzene complex is ca. 2000 times more reactive than the chlorobenzene complex. The difference is taken as evidence for a rate-limiting attack on the arene ligand followed by fast loss of halide the concentration of the cyclohexadienyl anion complex does not build up. In the reaction of fluorobenzene-Cr(CO)3 with amine nucleophiles, the coordinated aniline product appears rapidly at 25 °C, and a carefiil mechanistic study suggests that the loss of halide is now rate limiting. 

The direct combination of selenium and acetylene provides the most convenient source of selenophene (76JHC1319). Lesser amounts of many other compounds are formed concurrently and include 2- and 3-alkylselenophenes, benzo[6]selenophene and isomeric selenoloselenophenes (76CS(10)159). The commercial availability of thiophene makes comparable reactions of little interest for the obtention of the parent heterocycle in the laboratory. However, the reaction of substituted acetylenes with morpholinyl disulfide is of some synthetic value. The process, which appears to entail the initial formation of thionitroxyl radicals, converts phenylacetylene into a 3 1 mixture of 2,4- and 2,5-diphenylthiophene, methyl propiolate into dimethyl thiophene-2,5-dicarboxylate, and ethyl phenylpropiolate into diethyl 3,4-diphenylthiophene-2,5-dicarboxylate (Scheme 83a) (77TL3413). Dimethyl thiophene-2,4-dicarboxylate is obtained from methyl propiolate by treatment with dimethyl sulfoxide and thionyl chloride (Scheme 83b) (66CB1558). The rhodium carbonyl catalyzed carbonylation of alkynes in alcohols provides 5-alkoxy-2(5//)-furanones (Scheme 83c) (81CL993). The inclusion of ethylene provides 5-ethyl-2(5//)-furanones instead (82NKK242). The nickel acetate catalyzed addition of r-butyl isocyanide to alkynes provides access to 2-aminopyrroles (Scheme 83d) (70S593). 

The synthesis of 2-chloro-2,3,3-trifluorocyclobutyl acetate illustrates a general method of preparing cyclobutanes by heating chlorotrifluoroethylene, tetrafluoroethylene, and other highly fluorinated ethylenes with alkenes. The reaction has recently been reviewed.11 Chlorotrifluoroethylene has been shown to form cyclobutanes in this way with acrylonitrile,6 vinylidene chloride,3 phenylacetylene,7 and methyl propiolate.3 A far greater number of cyclobutanes have been prepared from tetrafluoroethylene and alkenes 4,11 when tetrafluoroethylene is used, care must be exercised because of the danger of explosion. The fluorinated cyclobutanes can be converted to a variety of cyclobutanes, cyclobutenes, and butadienes. 

Hydration of Substituted Phenylacetylenes in Acetic Acid Water Sulfuric Acid at 50.2°C (17)... 

In contrast to the above behavior, in the presence of. 1 M LiBr phenylacetylene yields the trans dibromide, C6HsCBr=CHBr, in greater than 99% yield upon the addition of Brj in acetic acid (35). This difference in behavior between the two systems has been accounted for by the formation of a different intermediate ion, 13, in the latter case. 

Figure 2. General ton-pair scheme for the addition of bromine to phenylacetylene in acetic acid (33).

Trumbo, D. L. et al J. Polym. Sci., A, Polymer Chem., 1987, 25, 1027-1034 Among palladium(II) salts used to polymerise phenylacetylene, the acetate led to rapid and very exothermic polymerisation, sometimes leading to explosion. 

A mixture of phenylacetylene and the pure ( anhydrous) acid prepared at — 180°C exploded when allowed to warm to — 78° C, possibly owing to formation of unstable 1-phenylethenyl perchlorate [1]. Reaction of various phenylacetylenes in acetic acid at 40° C is controllable [2],... 

Phenyl acetate Phenylacetonitrile Phenylacetylene (—)-3-Phenyl-1 -alanine a-Phenylbenzeneacetic acid 31.27... 

A similar H2 activation mechanism was proposed for the [Pd(NN S)Cl] complexes (5 in Scheme 4.5) in the semi-hydrogenation of phenylacetylene [45] after formation of the hydride 14 (Scheme 4.9), coordination of the alkyne occurs by displacement of the chloride ligand from Pd (15). The observed chemos-electivity (up to 96% to styrene) was indeed ascribed to the chloride anion, which can be removed from the coordination sphere by phenylacetylene, but not by the poorer coordinating styrene. This was substantiated by the lower che-moselectivities observed in the presence of halogen scavengers, or in the hydrogenations catalyzed by acetate complexes of formula [Pd(NN S)(OAc)]. Here, the acetate anion can be easily removed by either phenylacetylene or styrene. 

Phenyl acetates, hydrolysis of, and derivatives, catalytic action of cycloamyloses on, 23 222-228, 254 Phenylacetylene hydration, 41 155... 

Domino-Heck Reactions-General Procedure 5.6 mg (25 pmol) of palladium(II) acetate and 55 pmol of the arsine ligand were dissolved in 3 ml of dry dimethyl formamide and the solution was stirred at 65°C (40°C for trimethylsilylacetylene) for 15 mitt Then, 127 mg (1.35 mmol) N-Benzoyl-2-azabicyclo[2.2.1]hept-5-en-3-one, 1 mmol of the aryl compound. Four hundred and eighty-eight microliters (3.50 mmol) of triethylamine, and 3.00 mmol of the phenylacetylene (or silylmethyl-acetylene) were added rapidly in one portion. The mixture was heated at the same temperature for 24 h. After cooling down to room temperature 50 ml of brine were added, the reaction mixture was extracted with ethyl acetate and dried over MgSO. The solvent was evaporated, the residue purified by column chromatography (n-Hexan-Ethyl acetate 4 1). 

Oxidative coupling, phenylacetylene to. diphenyldiacetylene with cupric acetate, 46,39... 

To a saturated solution of 5.5 g. (0.028 mole) of finely powdered cupric acetate monohydrate (Note 1) in 20 riil. of a 1 1 by volume pyridine-methanol mixture (Notes 2, 3, 4, and 5) contained in a 50-ml. round-bottomed flask fitted with a reflux condenser is added 2.0 g. (0.0196 mole) of phenylacetylene (Note 6). The deep-blue suspension becomes green when heated under reflux. After 1 hour of heating, the solution is cooled (Note 7) and added dropwise to 60 ml. of 18N sulfuric add, with stirring and external cooling in an ice-salt freezing mixture (Note 8). The resulting white suspension is extracted with three 25-ml. portions of ether, and the combined ethereal extracts are washed with 15 ml. of... 

Phenylacetylenes (3 mol) react with Te02 (1 mol) and excess of lithium halide in refluxing HOAc to produce 3-halobenzotellurophenes via the addition of a Te(IV) acetate halide to the triple bond, cychzation (probably by loss of HOAc) and reduction of the Te(IV) cyclic product to 3-halobenzotellurophene by an excess of the phenylacetylene. Owing to isolation facihties, the product is converted into the crystalhne dichlorides that is reduced to the benzotellurophenes. °... 

Bromobenzotellurophene ° A mixture of 2.0 g (19.6 mmol) of phenylacetylene, 1.0 g (6.3 mmol) of tellurium dioxide, 2.0 g (23 mmol) of lithium bromide aud 50 uiL of acetic acid is heated uuder reflux for 20 h, cooled to 20°C, aud poured iuto 150 uiL of diethyl ether. Aqueous sodium hydrogeu carbouate solutiou (5%) is added uutil all the acid has beeu ueutralized. The orgauic phase is separated, dried with auhydrous calcium chloride, fdtered aud evaporated. The browu, oily residue is dissolved iu a mixture of 30 mL of carbou tetrachloride aud 10 mL of petroleum ether (b.p. 30 0°C). Chloriue is carefully bubbled through this solutiou uutil precipitatiou of the product ceases. The yellow precipitate is filtered and recrystallized from acetonitrile. Yield 2.2 g (92%) m.p. 263-265°C. 

The reaction of carbazole with phenylacetylene in alkaline dimethyl sulfoxide gave the Z-alkene (41). Reaction of carbazole with the acetals... 

The air oxidation of phenylacetylene and secondary amines in the presence of cupric acetate in benzene solution yields ynamines [22], This reaction requires only catalytic amounts of cupric salts and gives high conversions in less than 30 min when the Cu+2/phenylacetylene ratio is only 0.02. Only 1,4-diphenylbutadiyne is produced if the stoichiometric amount of cupric ion is used in the absence of oxygen. The yield of ynamine can be increased from 45 to 90 % if the stoichiometric amounts of a reducing agent such as hydrazine are continuously added during the course of the reaction. The use of primary amines under similar conditions yields the acetamide derivative. 

To a flask containing 2.0 gm (0.01 mole) of cupric acetate in 25 ml (0.38 mole) of dimethylamine in 100 ml of benzene at 5°C are added dropwise simultaneously a solution of 5.1 gm (0.05 mole) of phenylacetylene in 100 ml of benzene over 30 min and a stream of oxygen (1.0 ft3/hr). The oxygen stream is added for 30 min more after the phenylacetylene addition has been completed. The copper ions are precipitated by adding 100 ml of ice water. The organic layer is separated, dried, and concentrated under reduced pressure. A gas chromatograph of the crude (column 10 ft x in. 410 gum rubber) showed two peaks N, A-dimethylamino-2-phenylacetylene and 1,4-diphenylbutadiyne. The ynamine was obtained in 40 % yield as determined by reaction of the crude... 

The method has been applied by the submitters2 to the preparation of cyclohexylmethylpropiolaldehyde diethyl acetal (54% yield) from cyclohexylmethylacetylene and triethyl orthoformate of phenylethynyl n-butyl dimethyl ketal (40% yield) from phenylacetylene and trimethyl -orthovalerate and of phenylethynyl methyl diethyl ketal (34% yield) from phenylacetylene and triethyl orthoacetate. w-B utylpropiolaldehyde diethyl acetal was isolated in 32% yield by heating an equimolar mixture of 1-hexyne and triethyl orthoformate containing catalytic amounts of a zinc chloride-zinc iodide catalyst under autogenous pressure at 190° for 3 hours. 

Well-controlled polymerization of substituted acetylenes was also reported. A tetracoordinate organorhodium complex induces the stereospecific living polymerization of phenylacetylene.600 The polymerization proceeds via a 2-1 -insertion mechanism to provide stereoregular poly(phenylacetylene) with m-transoidal backbone structure. Rh complexes were also used in the same process in supercritical C02601 and in the polymerization of terminal alkyl- and arylacetylenes.602 Single-component transition-metal catalysts based on Ni acetylides603 and Pd acet-ylides604 were used in the polymerization of p-diethynylbenzene. 

With monosubstituted acetylenes, such as phenylacetylene (94) and propiolaldehyde diethyl acetal (95), the orientation of phenyl azide is determined both by electronic and steric effects.307 08... 

---