Alkyne complexes preparation

Treatment of tantalum-alkyne complexes, prepared in situ from TaCls, Zn and RC=CR (R = n-C5Hn), with the lithio-imine Li N=CR Me (R = n-CgHn), followed by aqueous NaOH, gives primary ( )-allylic amines E-RCH=CR-CR Me(NH2). Treatment of these complexes with the terminal alkyne R"C=CH (R" = n-CeHis), followed by aqueous NaOH, yields tetrasubstituted benzene derivatives (99a-d). ... 

Electrophilic attack on olefin ligands coordinated to electron-rich, strongly backbonding metals is illustrated by the reactions of (P group 4 olefin and alkyne complexes, as well as some electron-rich olefin complexes. Zirconocene- and and hafnocene-olefin complexes generated by reaction of zirconocene dichloride with two equivalents of alkyl lithium and isolated upon addition of a phosphine ligand react with carbonyl compounds and weak protic acids to form insertion products and alkyl complexes. Several examples of the reactions of these complexes with electrophiles are shown in Equations 12.65-12.66. Zirconocene-alkyne complexes prepared by thermolysis of vinyl alkyl complexes and titanium-alkyne complexes generated by the reduction of Ti(OPr ) also react with electrophiles, such as aldehydes and acid, to form products from insertion into the M-C bond and protonation of the M-C bond respectively. 

One of the most interesting arylcopper(I) compounds is mesitylcopper(I), which is a pentamer in the solid state and a tetramer in the presence of S-ligands. It has recently been shown to split dioxygen, and is highlighted here because it is prepared from CuCl. Hexafluoroacetylacetonatocopper(I)-alkyne complexes (prepared from CuCl) have been shown to be useful in the chemical vapor deposition of Cu metal. ( )-l-TrimethylsUyl-l-alkenes have been prepared in high yields by the CuCl-catalyzed decomposition of a-trimethylsilyldiazoalkanes. Finally, Indian chemists have shown that 1,2-diketones are produced in good yield when Na(RCO)Fe(CO)4 is treated with CuCl. ... 

AUylzirconium complexes are conveniently obtained by the regio- and stereoselective hydrozirconation of allene [127-133] and can be, for example, used subsequently for the MAO-catalyzed allylzirconation of alkynes to prepare enyne derivatives [132]. Alternatively, the preparation of (E)-l,3-dienes from aldehydes and the appropriate allylstannane zirconocene derivative (R = SnBu,) is accomplished (Scheme 8-17) [131], Note that addition of [Cp2Zr(H)Cl[n (1) on the aUenyl reagent with the... 

Even larger, conjugated systems were synthesized by employing both difunctional isocyanides and difunctional alkynes. In all the cases, the components have structural rigidity, which lends rigid-rod character to the complexes prepared from them. Many of the complexes are associated via intermolecular aurophilic contacts, which appear to have a distinct influence on the photophysical behavior, but are as yet not a necessary condition for luminescence (Scheme 51).196... 

As described in this chapter, vinylidene complexes of Group 6 metals have been utilized for the preparation of various synthetically useful compounds through electrophilic activation or electrocyclization of terminal alkyne derivatives. These intermediates are quite easily generated from terminal alkynes and M(CO)6, mostly by photo-irradiation and will have abundant possibilities for the catalytic activation of terminal alkynes. Furthermore, it should be emphasized that one of the most notable characteristic features of the vinylidene complexes of Group 6 metals is their dynamic equilibrium with the it-alkyne complex. Control of such an equilibrium would bring about new possibilities for unique metal catalysis in synthetic reactions. 

Ruthenium vinylidene species can be transformed into small carbocyclic rings via carbocyclization reactions. Ruthenium vinylidene complex 2, generated from the electrophilic reaction of alkyne complex 1 with haloalkanes, was deprotonated with "BU4NOH to give the unprecedented neutral cyclopropenyl complex 3 (Scheme 6.2) [5]. Gimeno and Bassetti prepared ruthenium vinylidene species 4a and 4b bearing a pendent vinyl group when these complexes were heated in chloroform for a brief period, cyclobutylidene products 5a and Sb formed via a [2 + 2] cycloaddition between the vinylidene Ca=Cp bond and olefin (Scheme 6.3) [6]. 

In both of the Ni-mediated steps in this synthesis, the Ni-alkyne complex is acting as an acyl anion, in one case opening an epoxide and in the other case adding to the aldehyde in an intramolecular sense. Such Ni-reduced phenylalkynes are among the easiest to prepare and least expensive of acyl anion equivalents. 

Green and coworkers19 prepared the title compound and other related monoalkyne complexes by reaction of the corresponding bis(alkyne) complex with triphenylphosphine (or other phosphines) in good yields. The method described here works for several alkynes, for example, 2-butyne or phenyl-acetylene, and also for phosphines, for example, PEt3 or P(OPh)3. 

The alkyne complex [MoI C(NHBu ) 2(CNBu )4]+ results from reductive coupling upon reduction of [MoI(CNBut)6]+ la The thiolate-isocyanide complex [Mo(SBu )2(CNBu,)4], prepared from [Mo(SBu )4] and CNBu, forms the adduct [Mo(CNBu )4(p-SBu )2CuBr]. All these compounds have been structurally characterized.73... 

These reactions can be used to prepare a novel series of complexes where cyclic alkynes can be stabilized by coordination to platinum(O).831,832 The compounds are feasible because coordination of a triple bond to platinum causes a distortion of the alkyne from linearity by displacement of the alkynic substituents back away from the platinum. Also these methods can be used to prepare platinum(O) alkyne complexes with substituents other than triphenylphosphine.833-836... 

Figure 8 The preparations and crystal structures of copper(I) alkene and alkyne complexes... 

Bis(adamantylimido) compounds, with monomeric chromium(VI) complexes, 5, 348 Bis(alkene) complexes conjugated, Rh complexes, 7, 214 mononuclear Ru and Os compounds, 6, 401 -02 in Ru and Os half-sandwich rj6-arenes, 6, 538 with tungsten carbonyls and isocyanides, 5, 685 Bis(u-alkenylcyclopentadienyl) complexes, with Ti(II), 4, 254 Bis(alkoxide) nitrogen-donor complexes, with Zr(IV), 4, 805 Bis(alkoxide) titanium alkynes, in cross-coupling, 4, 276 Bis(alkoxo) complexes, with bis-Cp Ti(IV), 4, 588 Bis[alkoxy(alkylamino)carbene]gold complexes, preparation, 2, 288... 

Bis(alkyl) complexes, with mercury, preparation, 2, 428 Bis(alkylidene)s, in Ru and Os half-sandwiches, 6, 583 Bis(alkylimido) complexes, with chromium(VI), 5, 346 Bis(rj2-alkyne)platinum(0) complexes, preparation, 8, 640 Bis(alkynyl) complexes in [5+2+l + l]-cycloadditions, 10, 643 with manganese, 5, 819 with mercury, preparation, 2, 426 mononuclear Ru and Os compounds, 6, 409 with platinum, 12, 125 with platinum(II), 8, 539 with titanium(IV), 4, 643 with zirconium, 4, 722... 

Bis(cyclooctene)—iridium(I) complexes, preparation, 7, 316 Bis(cyclopentadienyl) alkenes, with tantalum, 5, 157 Bis(cyclopentadienyl) alkyne niobium complexes, characteristics, 5, 81... 

Bis(phosphoranimine) ligands, chromium complexes, 5, 359 Bis(pinacolato)diboranes activated alkene additions, 10, 731—732 for alkyl group functionalization, 10, 110 alkyne additions, 10, 728 allene additions, 10, 730 carbenoid additions, 10, 733 diazoalkane additions, 10, 733 imine additions, 10, 733 methylenecyclopropane additions, 10, 733 Bisporphyrins, in organometallic synthesis, 1, 71 Bis(pyrazol-l-yl)borane acetyl complexes, with iron, 6, 88 Bis(pyrazolyl)borates, in platinum(II) complexes, 8, 503 Bispyrazolyl-methane rhodium complex, preparation, 7, 185 Bis(pyrazolyl)methanes, in platinum(II) complexes, 8, 503 Bis(3-pyrazolyl)nickel complexes, preparation, 8, 80-81 Bis(2-pyridyl)amines... 

Dicarboxypyridine, with trinuclear Os clusters, 6, 747 Dichalcogenides, addition to alkynes, 10, 752 Di(/i4-chalcogenido)tetrairon complexes, preparation, 6, 277... 

Indenyl)rhodium(I) complexes, preparation, 7, 184—185 Indium complexes acid halide reactions, 9, 683 in alkene and alkyne allyindations, 9, 693 alkyl, aryl, alkynyls, 3, 288 in alkynylations, 9, 720... 

Polymetallic alkynes, with platinum heterobimetallic derivatives, 8, 647 homobimetallic complexes, 8, 645 polymetallic derivatives, 8, 648 Polymetallic cyclopentadienyl iridium complexes, preparation and characteristics, 7, 370... 

Three zirconium/cycloheptadienyne complexes (231a-c) have been prepared by /3-hydrogen elimination from a mixture of cycloheptatrienyl complexes 269-271 (Scheme 33) and have been used as intermediates for the preparation of a zirconaazulene.87 The alkyne complexes are formed to the exclusion of the allene isomer 268. This is believed to be due to the proximity of the /3-vinyl hydrogen that is a result of both the shorter double bond and its forced coplanarity with the metal. Allene formation from 269 might be induced by blocking the vinyl position (see Sections IV,B and IV,C), but this has not been tested. 

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