Diphenylacetylene, reaction with

The reaction chemistry of germyne 172 has been investigated. Reaction with diphenylacetylene produces the digermacyclobutadiene 179 (Equation (326)), while treatment with excess trimethylsilylacetylene affords the bicyclic compound 180 (Scheme 69), which results from the formation of a biradical intermediate.394... 

The Pt2Ru4(CO)i8 cluster reacts with H2 to form Pt3Ru6(CO)2i(/i3-H)-(jt-H)3 in which the platinum and ruthenium atoms are arranged in triangular layers of the pure elements.10 This complex can be converted to Pt3Ru6(CO)20(/i3-C2Ph2X/i-H)2 by reaction with diphenylacetylene.10 The latter complex was found to be an active catalyst for the hydrogenation... 

Trapping of an intermediate silylene by reaction with diphenylacetylene to form a pseudo-pentacoordinate silole (209) was reported243. The silylene was obtained by a Ni(0)-catalyzed degradation of 92f (X = SiPh3, Y = Me, Z = H)243. 

Treating the sterically encumbered zirconocene ZrCFfn-CslliiBi F with "BuLi in the presence of ethene also provides a structurally characterised zirconocyclo-pentane Zr(C4H8)(r -C5H3Bu2)2 18. The reversibility of metallacycle formation was demonstrated by its reaction with diphenylacetylene to provide the zirconacyclo-pentene 19 incorporating the alkyne and one equivalent of ethene 22... 

The reaction mechanism can be explained by the formation of a dimethylsilylene intermediate which is able to undergo an insertion reaction into a Si—H bond (for more about this type of reaction, see Chapter 7 Silylenes). The formation of the silylene can be explained by an a elimination from the n metal-complexed disilane. The presence of the silylene has been proved by a capture reaction with diphenylacetylene, when the expected 1,1,4,4-tetramethyl-1,4-disilacyclohexa-diene could be isolated. 

The evidence for the formation of dimethylsilylene from 7-silanoboradiene includes reactions with diphenylacetylene, ethylene, etc., and the observed polymerization to dimethylpolysilane. 

The most interesting point in these reactions is the ring contraction, which takes place in the intermediate digermacyclohexadienes 46 and 47 during reaction with diphenylacetylene (Scheme 18)51. Thus, during thermolysis of the bicyclic... 

The major product of the reaction of [(rj -CplaTiMea] with dimethylacetylene is the titanacyclopentene 161 (R = Me) <2000POL879>. With diethylacetylene metallacycle, 161 (R = Et) is formed. Thermolysis of bis(methylcy-clohexenyljzirconocene in the presence of trimethylphosphine and further reaction with diphenylacetylene gives 162. Allene complex 163 reacts with 2-butyne or diphenylacetylene to yield the titanacyclopentenes 164 (R = Me, Ph). 

REACTION PRODUCTS AND ORGANOMETALLIC INTERMEDIATES WITH NICKEL(0) COMPLEXES. Nickel(O) complexes such as (Cod)2Ni, show a striking parallel with lithium(0) complexes in their reactions with diphenylacetylene a sequence of monomolecular reduction bimolecular, stereospecific reduction and cyclotrimerization (Scheme IX). Consonant with the suggestion that nickel(0) forms nickelirene (26) and nickelole (27) intermediates in the course of cyclotrimerization of diphenylacetylene is the isolation of (Z)-l,2-di-phenylethene (28) and (E,E)-1,2,3,4-tetraphenyl-l,3-butadiene (29) upon hydrolysis. Furthermore, when DC1 was used in the workup, both 28 and 29... 

Tungsten (0) catalyzed reaction of silacyclopropenes proceeds in a quite different fashion from the nickel and palladium catalyzed reactions [89]. Tungsten catalyzed abstraction of mesitylmethylsilylene from the silacyclopropene was observed, which is followed by the reaction with diphenylacetylene to give 87. 

A rich chemistry of clusters of the type [Ru3(//-H)(//3-apy)(GO)9] 6 (apy = 2-aminopyridine) has developed in the last decade. In reactions with alkynes edge-bridged cr,7r-alkenyl derivatives are obtained. The position and orientation of the alkenyl group within the ligand framework in these clusters depends on the presence or absence of subsituents on the amidic nitrogen atom." The phosphane-substituted clusters 65 and 66 also afford cr,TT-alkenyl derivatives on reaction with diphenylacetylene as shown in Scheme Under these reaction... 

Addition to Multiple Bonds. Kinetic measurements of the addition of acrylic acid and its methyl ester have shown this reaction to be first-order in both thiourea and alkenes. Divinyl sulphides (27) and (28) are formed from the corresponding alkynes and thioureas, but rearrangement is observed in the reaction with diphenylacetylene to give (PhaC=CH)2S. S-Vinyl-isoselenourea (29) is obtained from the addition of selenourea to I,3-diphenylprop-2-yn-l-one,... 

NHC-stabilized dichlorosilylene was shown to exhibit similar behavior in oxidative addition reactions (Scheme 16), i.e., formation of a SiOC three-membered heterocycle upon addition of benzophenone (74), whereas in the reaction withbenzil, the formation of a five-membered heterocycle is favored (75) [110]. The reaction with diphenylacetylene involves silylene oligomerization to also yield a compound with five-membered silacycle (76) [109]. 

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