Acetylide Coupling Research Articles

TRANSITION METAL, NON-METAL CARBONYL CLUSTRS AS SUPPORTS FOR UNUSUAL ACETYLIDE REACTIVITY

Group 16 elements serve as useful bridging and stabilising single atom ligands in mixed-metal carbonyl complexes and impart unusual reactivity on coordinated acetylenic moieties. Reactions of [Fe 3 (CO) 9 (μ 3 -E) 2 ] (E = S, or Se) with mononuclear acetylide complexes, [CpM(CO)_3-x(CCR)] (M = Mo or W, x = 0, R = Ph; M = Fe, x = 1, R = Ph or ferrocenyl) under facile conditions yield complexes featuring acetylide coupling, acetylide-flip and formation of oxo and acetylide-bridged complexes. In presence of free acetylenes, unusual ligand systems arising from C─S bond formation are observed and under certain conditions, formation of quinones by coupling of acetylenes with carbon monoxide is facilitated.

Use of a Sonogashira—Acetylide Coupling Strategy for the Synthesis of the Aromatic Spiroketal Skeleton of γ‐Rubromycin (VII).

AbstractFor Abstract see ChemInform Abstract in Full Text.

Generation and Coupling of [Mn(dmpe)2(CCR)(CC)]. Radicals Producing Redox‐Active C4‐Bridged Rigid‐Rod Complexes

The symmetric d(5) trans-bis-alkynyl complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(2)] (R = Me, 1 a; Et, 1 b; Ph, 1 c) (dmpe = 1,2-bis(dimethylphosphino)ethane) have been prepared by the reaction of [Mn(dmpe)(2)Br(2)] with two equivalents of the corresponding acetylide LiC triple bond CSiR(3). The reactions of species 1 with [Cp(2)Fe][PF(6)] yield the corresponding d(4) complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(2)][PF(6)] (R = Me, 2 a; Et, 2 b; Ph, 2 c). These complexes react with NBu(4)F (TBAF) at -10 degrees C to give the desilylated parent acetylide compound [Mn(dmpe)(2)(C triple bond CH)(2)][PF(6)] (6), which is stable only in solution at below 0 degrees C. The asymmetrically substituted trans-bis-alkynyl complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(C triple bond CH)][PF(6)] (R = Me, 7 a; Et, 7 b) related to 6 have been prepared by the reaction of the vinylidene compounds [Mn(dmpe)(2)(C triple bond CSiR(3))(C=CH(2))] (R = Me, 5 a; Et, 5 b) with two equivalents of [Cp(2)Fe][PF(6)] and one equivalent of quinuclidine. The conversion of [Mn(C(5)H(4)Me)(dmpe)I] with Me(3)SiC triple bond CSnMe(3) and dmpe afforded the trans-iodide-alkynyl d(5) complex [Mn(dmpe)(2)(C triple bond CSiMe(3))I] (9). Complex 9 proved to be unstable with regard to ligand disproportionation reactions and could therefore not be oxidized to a unique Mn(III) product, which prevented its further use in acetylide coupling reactions. Compounds 2 react at room temperature with one equivalent of TBAF to form the mixed-valent species [[Mn(dmpe)(2)(C triple bond CH)](2)(micro-C(4))][PF(6)] (11) by C-C coupling of [Mn(dmpe)(2)(C triple bond CH)(C triple bond C*)] radicals generated by deprotonation of 6. In a similar way, the mixed-valent complex [[Mn(dmpe)(2)(C triple bond CSiMe(3))](2)(micro-C(4))][PF(6)] [12](+) is obtained by the reaction of 7 a with one equivalent of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). The relatively long-lived radical intermediate [Mn(dmpe)(2)(C triple bond CH)(C triple bond C*)] could be trapped as the Mn(I) complex [Mn(dmpe)(2)(C triple bond CH)(triple bond C-CO(2))] (14) by addition of an excess of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) to the reaction mixtures of species 2 and TBAF. The neutral dinuclear Mn(II)/Mn(II) compounds [[Mn(dmpe)(2)(C triple bond CR(3))](2)(micro-C(4))] (R = H, 11; R = SiMe(3), 12) are produced by the reduction of [11](+) and [12](+), respectively, with [FeCp(C(6)Me(6))]. [11](+) and [12](+) can also be oxidized with [Cp(2)Fe][PF(6)] to produce the dicationic Mn(III)/Mn(III) species [[Mn(dmpe)(2)(C triple bond CR(3))](2)(micro-C(4))][PF(6)](2) (R = H, [11](2+); R = SiMe(3), [12](2+)). Both redox processes are fully reversible. The dinuclear compounds have been characterized by NMR, IR, UV/Vis, and Raman spectroscopies, CV, and magnetic susceptibilities, as well as elemental analyses. X-ray diffraction studies have been performed on complexes 4 b, 7 b, 9, [12](+), [12](2+), and 14.

Use of a sonogashira-acetylide coupling strategy for the synthesis of the aromatic spiroketal skeleton of gamma-rubromycin.

[reaction: see text] The synthesis of the fused aromatic spiroketal core of gamma-rubromycin is described via addition of an aryl acetylide fragment to an aryl acetaldehyde fragment. In turn, the aryl acetylene precursor was readily prepared with use of a Sonogashira reaction.

Evolution in the palladium-catalyzed cross-coupling of sp- and sp2-hybridized carbon atoms.

Palladium-catalyzed bond-formation between alkynes and aryl halides and triflates is as fascinating today as it was nearly 30 years ago when such reactions were introduced by Sonogashira (see scheme; OTf=CF3SO3). More facile procedures, new acetylide coupling partners, and more efficient catalysts and ligand systems all combine to expand the limits of this versatile reaction.

Synthesis, structure and mechanism of formation of chalcogen-stabilised mixed-metal clusters featuring acetylide bridging and acetylide coupling

Mild thermolysis of a toluene solution of [(η5-C5H5)Mo(CO)3(CCPh)] and [Fe3(CO)9(μ3-E)2] (E = S, Se) resulted in the formation of mixed-metal clusters, [(η5-C5H5)2Mo2Fe3(CO)8(μ3-E)2{μ5-CC(Ph)CC(Ph)}] (E = S, 1; Se, 2), [(η5-C5H5)2Mo2Fe4(CO)9(μ3-E)2(μ4-CCPh)2] (E = S, 3; Se, 4) and [(η5-C5H5)2Mo2Fe3(CO)7(μ3-E)2{μ5-CC(Ph)C(Ph)C}] (E = S 5; E = Se 6) which feature head-to-tail coupling of two acetylide groups, two acetylide groups which remain uncoupled and a tail-to-tail coupling of two acetylide groups, respectively, on the chalcogen-bridged Fe/Mo cluster framework. Under similar conditions, the reaction of [(η5-C5H5)W(CO)3(CCPh)] and [Fe3(CO)9(μ3-E)2] formed the clusters [(η5-C5H5)2W2Fe3(CO)7(μ3-E)2(μ3-η2-CCPh)(μ3-η1-CCH2Ph)] (E = S, 7 or Se, 8) and [(η5-C5H5)WFe2(CO)8(μ-CCPh)] (9). All compounds have been characterised by IR and 1H and 13C NMR spectroscopy. The Se-bridged compounds have been further characterised by 77Se NMR spectroscopy. The crystal structures of 1, 3 and 5–9 were elucidated by X-ray diffraction methods.

Coordinatively and Electronically Unsaturated Tetraruthenium Clusters: Reversible Triple CO Addition to Ru4(CO)9(μ-PPh2)[μ4-Ph2PCC(Ph)CC(Ph)

Two electronically unsaturated tetraruthenium clusters, Ru4(CO)9(μ-PPh2)[μ4-Ph2PCC(Ph)CC(Ph)] (2) and Ru4(CO)10(μ-PPh2)[μ4-Ph2PC(Ph)CCC(Ph)] (3), with spiked-triangular and open-chain structures have been synthesized via head-to-tail and head-to-head coupling of binuclear acetylides: cluster 2 contains a coordinatively unsaturated metal center and undergoes a fully reversible triple addition of carbon monoxide to afford Ru4(CO)11(μ-PPh2)[μ4-Ph2PC(O)CC(Ph)CC(Ph)] (4).

Stereoselective synthesis of a terpyrrolidine unit, a potential building block for anion recognition

The first stereoselective synthesis of a trans-threo-trans-threo-trans terpyrrolidine was achieved. A bidirectional strategy involving double acetylide coupling of two trans-N-BOC-pyrrolidine-aldehydes 3, epimerisation-free hydrogenation and ring closure via a seven-membered cyclic sulfate gives access to the terpyrrolidine scaffold.

Synthesis of Fe4(CO)8(µ-PPh2)2(µ4-η1,η1,η2,η2-C2Ph)2via coupling of acetylides at a binuclear centre: a molecule with through-the-cluster carbon–carbon bonding?

Thermolysis of Fe2(CO)6(µ-PPh2)(µ-η1,η2-C2Ph) affordsthe rectangular cluster Fe4(CO)8(µ-PPh2)2(µ4-η1,η1,η2,η2-C2Ph)2 with two face-capping acetylides linked through the Fe4 face by a short carbon–carbon contact: reaction with CO leads to Fe3(CO)8{µ-Ph2PC(CPh)C(CPh)PPh2} as a result of C–C and C–P bond-forming processes.

Synthesis of Molybdenum Complexes That Contain Silylated Triamidoamine Ligands. A .mu.-Dinitrogen Complex, Methyl and Acetylide Complexes, and Coupling of Acetylides

Synthesis of Molybdenum Complexes That Contain Silylated Triamidoamine Ligands. A .mu.-Dinitrogen Complex, Methyl and Acetylide Complexes, and Coupling of Acetylides

Reactions of Some Ferrocenyl- and 2-Thienylacetylenes

Abstract In an earlier paper, 1 we reported the preparation of a variety of ferrocenyl- and 2-thienylarylacetylenes via the coupling of cuprous acetylides with aryl iodides (eq 1). The ready availability of these acetylenes prompted us to examine some of their reactions under electrophilic and nucleophilic conditions.

C–C bond-making by trapping of a nucleophilic carbene (from an electron-rich olefin) by a σ–π-acetylido(hexacarbonyl)di-iron complex; X-ray crystal and molecular structure of [(OC)3FeC(+CNMeCH2CH2NMe)C̄(Ph)Fe(CO)3PPh2

Reaction of an electron-rich olefin [[graphic omitted]R′]2(R′= Me, Et, or CH2Ph) with the σ-π-acetylide [Fe2(CO)6(CCR)(PPh2)](R = Ph or But) yields the novel mesoionic complex [Fe2(CO)6(C2R)(PPh2){[graphic omitted]R′}]via carbene–acetylide coupling; X-ray analysis reveals that the carbene species is attached [C–C, 1·56(1)A] to the α-carbon atom [attached to Fe(1)] of the acetylide with the β-carbon atom bonded to Fe(2).

Acetylene–acetylide coupling via reactions of phosphido-bridged σ–π-acetylides with alkynes. X-Ray crystal structures of [Fe2(CO)5{PPh2C(O)C(But)CC(CO2Et)C(CO2Et)}] and [Fe2(CO)5{PPh2C(Ph)C(CO2Et)CC(But)CO}

Download options Please wait... Article information DOI https://doi.org/10.1039/C39760000896 Article type Paper Download Citation J. Chem. Soc., Chem. Commun., 1976, 896-898 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Acetylene–acetylide coupling via reactions of phosphido-bridged σ–π-acetylides with alkynes. X-Ray crystal structures of [Fe2(CO)5{PPh2C(O)C(But)CC(CO2Et)C(CO2Et)}] and [Fe2(CO)5{PPh2C(Ph)C(CO2Et)CC(But)CO}] W. F. Smith, N. J. Taylor and A. J. Carty, J. Chem. Soc., Chem. Commun., 1976, 896 DOI: 10.1039/C39760000896 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Wayne F. Smith Nicholas J. Taylor Arthur J. Carty