Diphenylbutadiyne, reaction with

The second option involves the incorporation of either chiral amines or chiral alcohols into the heteroatom-carbene side chain (R ), which represents the most versatile approach to diastereoselective benzannulation. The optically pure (2R,3R)-butane-2,3-diol was used to tether the biscarbene complex 37. The double intramolecular benzannulation reaction with diphenylbutadiyne allowed introduction of an additional stereogenic element in terms of an axis... 

Tetrahedrane (11) is the ruthenium analog of the much-studied tricobaltnonacarbonyl clusters Co3(CO)9CR see Cobalt Organometallic Chemistty). The substitution chemistry of (11) has been studied. A starting material is prepared from (11) by reaction with BX3 (equation 2), which gives the chloro and bromo compounds (12). In addition, (11) can also be treated directly with compounds such as diynes to yield interesting substitution products. For example, when (11) is refluxed in THF with diphenylbutadiyne, cis- and trans-alkene isomers of two alkyne insertion regioisomers are formed (equation 3). The product seems to arise from dehydrogenation of one end of the diyne to yield cis and trans enynes and an imsaturated monohydride cluster intermediate, which then reacts with the enynes to yield the allylic derivative products... 

Reaction of [Wl2(CO)3(NCMe)2] with equimolar quantities of 1,4-diphenylbutadiyne afforded397 the iodo-bridged dimer [ W(p,-I)(I)(CO)(NCMe)(Tl2-PhCCCCPh) 2] whereas with excess 1,4-diphenylbutadiyne the monomeric product [Wl2(CO)(NCMe)(T 2-PhCCCCPh)2] was obtained, which on reaction with further [Wl2(CO)3(NCMe)2] afforded the bimetallic 1,4-diphenylbutadiene complex [W2l4(CO)2(NCMe)2(li, n2 -T)2, q2. pijCCCcPh)2]. 

Double benzannulation can be applied to the diastereoselective synthesis of biaryls. Upon reaction with diphenylbutadiyne the biscarbene complex 96 bearing a Cj-symmetric (2J ,3R)-butane-2,3-diol bridge affords a single R,R,S-diastereomer of the tethered 2,2 -binaphthol 97 in moderate yield (Scheme 11.28) [53],... 

Organomagnesium derivatives have not so far been isolated [80JA994 80JOM(193)C13]. Bis[bis(trimethylsilyl)phosphonamide] with diphenylbutadi-yne and calcium or strontium in THE yields the TiyP)-coordinated species 129. Reaction of (THE)4Ba[P(SiMc3)2]2 with diphenylbutadiyne gives an ri -coordinated species 130 (98JA6722). 1-Chloro-and l-cyclopentadienyl-3,4-dimethyl-2,5-bis-(trimethylsilyl)-l-phosphacyclopenta-2,4-dienes both react with calcium to give... 

The reaction of Ba[P(SiMe3)2]2(THF)2 with diphenylbutadiyne in toluene for 12 days induces a m-addition of the diyne to the phosphide, followed by a 1,3-silyl group shift and ring closure. The dinuclear complex 132 is then isolated in good yield.283 Its complex structure contains Ba-C a bonds (2.881(5), 2.899(5) A), side-on Ba-alkyne (3.003(6), 3.363(6) A) and arene interactions, and Ba-phospholide bonds (Ba-P = 3.487(2) A) (Figure 65). 

The toroidal pressure probe, introduced in 1989 by Rathke and coworkers [249, 250], has been modified by Woelk and coworkers [249, 251], who have used a toroid cavity NMR autoclave for high pressure PHIP NMR experiments. Figure 1.43 shows the PHIP spectrum of the [Rh(norbornadiene)(PPh3)2]PF6-catalyzed hydrogenation of 1,4-diphenylbutadiyne with 40 bar of 50% emiched para-H2 [252]. The spectrum from the same reaction at ambient H2 pressure is shown in the inset [253]. The two absorption/emission PHIP patterns in both spectra indicate that para-H2 is transferred pairwise during the catalytic cycle. 

Figure 1.43 HP PHIP NMR spectrum of the [Rh(norbornadiene)(PPh3)2](PFd-catalyzed hydrogenation of 1,4-diphenylbutadiyne with 40 bar of 50% enriched P-H2, plus the spectrum from the same reaction at ambient H2 pressure (in the inset).

The CO insertion product is obtained in low yield. A similar reaction is observed with diphenylbutadiyne and diphenylcarbodiimide. ... 

Conjugated diynes can function as dienophiles in Diels-Alder reactions, and adducts have been obtained in which one or both of the triple bonds participates. Most of the studies have involved the use of substituted cyclopentadienones, e.g. tetraphenylcyclopentadienone ( tetracyclone ), which form adducts that undergo decarbonylation to give aromatic hydrocarbons. Butadiyne itself reacts with tetracyclone to give hexaphenylquaterphenyl (221) while diphenylbutadiyne gives the mono(222)- and di(223)-adduct . Bis(4-biphenylyl)butadiyne gives the monoadduct 224 . 

Reaction of AsH2(SiPr 3) with M[N(SiMe3)2]2 2(THF) (M = Ca or Sr) produces M[As(H)Si-Pr 3]2(THF)4, which is in equilibrium with the dimers M[As(H)SiPr 3][/.t-As(H)SiPr 3]3M(THF)3 by elimination of THF. Reaction of the equilibrium mixtures with diphenylbutadiyne gives the metal bis(THF)bis(2,5-diphenylarsolide) species. A mechanism based on intermolecular H/SiPri3 exchange has been proposed that explains the formation of both the [As(SiPr 3)2] and 2,5-diphenyl-3,4-bis(phenylethynyl)arsolide anions the latter was isolated as a solvent-separated ion pair with the binuclear [(THF)3Ca /i-As(H)SiPr 3 3Ca(THF)3]" " cation (see Figure 58). ... 

However, when the organometallic reagent was prepared by reaction of n-butyllithium on p-bromo styrene, a more complex reaction system resulted. Only a very poor yield of 1,4-diphenylbutadiyne (189) was obtained, together with various amounts of phenylacetylene. 10... 

The reaction of (phenylethynyl)magnesium bromide with tellurium tetrachloride afforded modest yields of the dialkynyltelluride (66) together with an equimolecular amount of 1,4-diphenylbutadiyne (22). Because of the difficulties for the purification, the dialkynyltelluride (66) was isolated as the diiodide in a 33% yield. 

A noncatalytic reaction of diphenylbutadiyne with benzylamine leads to 2,3,6-triphenylpyridine (2) in 50-70% yield (72TL3487). Interestingly, in the presence of CuCl the pyrrole pathway dominates, leading to l-benzyl-2,5-diphenylpyrrole (3) in 87% yield. 

Relative to the reactions presented in Scheme 12, the hydrophosphination of diynes with Ph2PH catalyzed by 5 mol% [Ca(PPh3)2(THF)4] proceeds with exceedingly low selectivties, despite the reaction being carried out at —78 °C. Westerhausen has examined a number of substituted 1,4-diynes under these conditions, and while reactions proceed in high yield and give predominantly twofold additirai of the phosphine to the diyne producing 1,4-addition products, an unfavorable mixture of all possible stereoisomers is observed (Scheme 13). In the case of 1,4-di-t-butylbutadiyne an additional aUene isomer was observed, while hydrophosphination of 1,4-diphenylbutadiyne yielded in addition to isomeric 1,4-addition products a 1,2-addition product (not represented in Scheme 13) [107, 108],... 

The CO insertion product is obtained in low yield. A similar reaction is observed with diphenylbutadiyne and diphenylcarbodiimide When the [2+2] cycloadduct derived from bis(trimethylsilyl)carbodiimide and a zir-conocene imide 32 is treated with diphenylacetylene a new metallacycle 33 is produced. Reaction of 33 with diisopropylcarbodiimide affords the six-membered ring metallacycle... 

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