Diphenyldiacetylene

Note that 1,4-substituted butadiynes with diazomethane can form two isomers. Kuznetsov and co-workers have considered this problem in detail and established that diphenyldiacetylene with diazomethane forms, in standard conditions (ether, 0°C, 9 days), only one of the two possible regioisomers 4-phenyl-3(5)-phenylethynylpyrazole (yield 86%) (93ZOB1107). The cyclization of derivatives of phenoxy-2,4-hexadiyn-6-oles with diazomethane leads to only one isomer of alkynylpyrazole (76MI1 77MI1) (Scheme 8). 

In the case of the reaction between 2-diazopropane and diphenyldiacetylene, the reverse (as compared with other diynes) orientation of addition of the first molecule of the diazo compound with a predominant formation of 4-phenylethynylpyrazole is observed. Therefore, it is noteworthy that whereas the regioselectivity of the addition of diazoalkanes to alkenes is well studied audits products have, as a rule, the structure been predicted with respect to electron effects, the problem of orientation... 

Phenoxy acetophenone, 46, 94 Phenylacetyleue, oxidative coupling to diphenyldiacetylene, 46, 39 partial reduction to styrene using palladium catalyst, 46, 90 reaction with sodium hypobromite to yield phenylbromoethyne, 46,86... 

Salts with the homoleptic [Au(C=CR)4]- anion have been obtained in only one case (R = Ph), with [nBu4N]+ as the counterion. The synthesis from (Me3P)Au(C=CPh)3 and PhC=CLi followed by precipitation with nBu4N+Br from thf requires carefully controlled conditions. It is accompanied by reductive elimination of diphenyldiacetylene to give [nBu4N]+[Au(G=CPh)2] as the byproduct. The crystal structure of the colorless, diamagnetic mixed-anion salt 2[nBu4N]+[Au(C=CPh)2] [Au(C=CPh)4] has been determined. The anions are linear and square planar, respectively.120... 

Diphenylcyclopropane, 48, 75 Diphenylcyclopropenone, 47, 62 Diphenyldiacetylene, 46,39 Diphenyl disulfide, oxidation to methyl... 

Similarly, when diphenyldiacetylenes having nitreno-groups at the m,p -and w,m -positions [30i] were generated, only the former showed a ground quintet state (Iwamura and Murata, 1989). 

The crude solid is purified by dissolving it in 50 ml. of petroleum ether (b.p. 40-60°) and introducing it on a short alumina column (IS g.j Brockmann Activity 1 or an equivalent chromatographic alumina). The column is then eluted with 300 ml. of a 1 9 mixture of ether-petroleum ether (b.p. 40-60°). Concentration of the eluate leaves a solid which is recrystallized from aqueous ethanol to give 1.4-1.6 g. (70-80%) of diphenyldiacetylene as large colorless needles, m.p. 87-88° (Note 10). 

Diphenyldiacetylene, 46,39 Diphenylmercury, reaction with aluminum to give triphenylaluminum, 46,708... 

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

Phenoxyacetophenone, 46, 94 Phenylacetylene, oxidative coupling to diphenyldiacetylene, 46,39 reaction with sodium hypobiomite to yield phenjdbromoethyne, 46, 86 Phenylacetyl fluoride, 46, 6 Phenylbrojioethyne, 46, 86 l-Phenyl-l,3-hutadiene, 46, 94 Phenyl (-butyl ether, 46, 89 />-Phenylene diisothiocyanate, 45, 21 Phenylethynyllithium 46, 88 Phenylethynymagnesium Grignard reagent, 46, 88... 

An 89% yield of diphenyldiacetylene was obtained when the" reaction was allowed to proceed for 24 hours at room temperature (20°). 

Dicyclopentadienyldinickeldiphenylbutadiyne-dicobalt hexacarbonyl has been prepared from diphenyldiacetylene in which one triple bond acts as a bridging group between two nickel atoms and the other between two cobalt atoms (203). Reduction of the diphenylacetylene complex (R = R = Ph) with sodium and alcohol in liquid ammonia yields dibenzyl, showing that the diphenylacetylene grouping is bonded only to the nickel atoms. The corresponding complex of acetylene (R = R = H) has also been prepared from nickeloccne and acetylene (69) ... 

Diphenylcyclopropenone, 47, 62 Diphenyldiacetylene, 45, 39 Diphenyl disulfide, oxidation to methyl benzenesulfinate, 46, 62 1,1-Diphenylethylene, reaction with N, -diphenylnitrone, 46,129 NjN -Diphenylethylenediamine, condensation with triethyl orthoformate, 47, 14... 

When phenylacetylenes (3 mol), tellurium dioxide (1 mol), and a lithium halide (14-18 mol) were refluxed in acetic acid, 3-halobenzotellurophenes were obtained in yields ranging from 21 to 92%2. A tellurium(IV) acetate halide, formed from tellurium dioxide, lithium halide, and acetic acid, probably adds to the carbon-carbon triple bond of the phenylacetylene. The intermediary 2-phenyl-2-haloethenyl tellurium acetate halide cyclizes probably by loss of acetic acid. The 3-halobenzotellurophene Te, 7e-acetate halide is then reduced to 3-halobenzotellurophene by an excess of the phenylacetylene. Diphenylacety-lene and diphenyldiacetylene did not react under these conditions. 

Diphenyltellurophene is obtained by treatment of diethyl ditelluride with diphenyldiacetylene in N2H4-KOH-DMSO-H2O at 55 °C (DMSO = dimethyl sulfoxide Scheme 17) <2002KGS280>. 

Formation of diphenyldiacetylene by the oxidation of the copper(i) salt of phenylacetylene was observed by Glaser over a century ago . The modern refinement of the reaction involves shaking an ethynyl compound with an aqueous... 

The electronic spectra of these cyclic acetylenes show characteristic features of diphenyldiacetylene and diphenylacetylene chromophores. However, they also... 

Figure 4. Schematic illustration of the p orbitals in the strained o,o -bridgcd and p,p -bridged diphenyldiacetylenes (147 and 148) (R = —OfCHjjnO—) . Reproduced by permission of the Chemical Society of Japan.

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