Novel preparation of σ-alkynyl complexes of transition metals by copper(<scp>I</scp>) iodide-catalysed dehydrohalogenation

Sonogashira, Kenkichi; Yatake, T.; Tohda, Yasuo; Takahashi, Shigetoshi; Hagihara, Nobue

doi:10.1039/c39770000291

Cited by 183 publications

(122 citation statements)

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“…100 The compounds were characterized by the usual suite of 1 H, 13 C and 31 P NMR spectroscopies, IR spectroscopy, mass spectrometry, and elemental analysis. Complexes 2a and 2b were also characterized by single crystal X-ray diffraction studies, the results of which are summarized in the ESI.…”

Section: Resultsmentioning

confidence: 99%

Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions

et al. 2017

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and break-off distance data, we demonstrate that a PPh 3 supporting ligand in the platinum complexes can provide an alternative contact point for the STM tip in the molecular junctions, orthogonal to the terminal CuCSiMe 3 group. The attachment of hexyloxy side chains to the diethynylbenzene ligands, e.g. trans-Pt{CuCC 6 H 2 (Ohex) 2 CuCSiMe 3 } 2 (PPh 3 ) 2 (Ohex = OC 6 H 13 ), hinders contact of the STM tip to the PPh 3 groups and effectively insulates the molecule, allowing the conductance through the full length of the backbone to be reliably measured. The use of trialkylphosphine (PEt 3 ), rather than triarylphosphine (PPh 3 ), ancillary ligands at platinum also eliminates these orthogonal contacts. These results have significant implications for the future design of organometallic complexes for studies in molecular junctions.

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Section: Resultsmentioning

confidence: 99%

Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions

et al. 2017

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“…The authors proposed a mechanism in which an organocopper intermediate, formed by C À H activation in the presence of the Cu complex and base, produces the transmetalation to Pd in the Pd/Cu double-co-catalytic mechanism. This proposal is based on the role assumed for Cu I in the Sonogashira reaction, [11,62,63] but Huang and co-workers do not exclude other pathways. [74] Decarboxylative cross-coupling processes: Goossen et al have introduced the decarboxylative cross-coupling processes, in which a copper(I) or a silver(I) catalyst mediates the extrusion of CO 2 from carboxylic acid salts, while a palladium complex catalyzes the coupling of the resulting carbon nucleophiles with carbon electrophiles.…”

Section: A C H T U N G T R E N N U N G (Pph 3 ) 2 ]/A C H T U N G T Rmentioning

confidence: 99%

“…Alkynyls-copper(I), [CuA C H T U N G T R E N N U N G (C CR)] n , have been reported to react readily with halide complexes of Ni II , Pd II , and Pt II , giving the corresponding alkynyl complexes (Scheme 2). [11] This method is used to prepare rigid-rod s-bonded alkynyl polymers. [11a,c, 12] Yamamoto et al carried out mechanistic studies on these reactions and proposed that the migration of the alkynyl ligand from Cu I to Pd II is a reversible step proceeding through bimetallic intermediates, as depicted in Scheme 3.…”

Section: Introductionmentioning

confidence: 99%

Bimetallic Catalysis using Transition and Group 11 Metals: An Emerging Tool for CC Coupling and Other Reactions

Pérez‐Temprano

Casares

Espinet

2012

Chemistry A European J

214

131

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Bimetallic catalysis refers to homogeneous processes in which either two transition metals (TM), or one TM and one Group 11 (G11) element (occasionally Hg also), cooperate in a synthetic process (often a C-C coupling) and their actions are connected by a transmetalation step. This is an emerging research area that differs from the isolated or tandem applications of the now classic processes (Stille, Negishi, Suzuki, Hiyama, Heck). Most of the reactions used so far combine Pd with a second metal, often Cu or Au, but syntheses involving very different TM couples (e.g., Cr/Ni in the catalyzed vinylation of aldehydes) have also been developed. Further development of the topic will soon demand a good knowledge of the mechanisms involved in bimetallic catalysis, but this knowledge is very limited for catalytic processes. However, there is much information available, dispersed in the literature, coming from basic research on exchange reactions occurring out of any catalytic cycle, in polynuclear complexes. These are essentially the same processes expected to operate in the heart of the catalytic process. This Review gathers together these two usually isolated topics in order to stimulate synergy between the bimetallic research coming from more basic organometallic studies and the more synthetic organic approaches to this chemistry.

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“…As in fullerenes, this geometry can be explained by the presence of alternating five and six-membered rings in the polycyclic aromatic hydrocarbon platform. The final step, which involved connecting the four triptycene wheels through a quadruple Sonogashira coupling process, [30] successfully afforded nanovehicle 9 in 34 % yield.…”

Section: Resultsmentioning

confidence: 99%

“…To test the reactivity of the four iodine centers towards Sonogashira coupling, [30] we performed such reactions with (3-cyanopropyl)dimethylsilylacetylene. The use of a (3-cyanopropyl)dimethylsilyl protecting group, which is a polar analogue of trimethylsilyl, [31] allowed the easy separation of the target molecule from the expected side-products (triyne, diyne, and monoyne).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Polycyclic Aromatic Hydrocarbon‐Based Nanovehicles Equipped with Triptycene Wheels

Rouville

Garbage

Cook

et al. 2012

Chemistry A European J

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Two new nanovehicles that have extended aromatic platforms as the cargo zones have been obtained. Two strategies were considered for the formation of the perylene core from two naphthalene precursors. The first was based on a Scholl-type reaction involving an oxidant, and the second used a brominated derivative to perform a homocoupling reaction. The first strategy failed under diverse coupling conditions in the presence of several strong oxidants. Nevertheless, the use of CoF(3) in trifluoroacetic acid triggered a dimerization reaction between two ester groups of one molecule and the naphthalene unit of another, thereby surprisingly yielding a ten-membered carbon macrocycle. The second strategy encountered a lack of reactivity of the substrate under several homocoupling conditions. The dimerization was not easily performed but Ullmann-type conditions ultimately gave the expected product. The low yield and low solubility of the product encouraged us to modify our initial design. The synthesis of a new chassis that incorporated additional tert-butyl groups improved the solubility of the molecules and also prevented overcyclization of the aromatic platform by blocking these positions. Some p-phenylene spacers were also intercalated between the iodine and perylene centers to increase the reactivity of the halide towards coupling reactions. Two new chassis were obtained by Scholl-type oxidative coupling using FeCl(3) as the oxidant. The introduction of four triptycene wheels allowed the formation of the two corresponding nanovehicles.

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Novel preparation of σ-alkynyl complexes of transition metals by copper(I) iodide-catalysed dehydrohalogenation

Abstract: Transition metal alkynyl complexes have been prepared conveniently in high yields under mild conditions by the direct reaction of acetylenes with metal halides in the presence of catalytic amounts of copper(1) iodide in diethylamine.

Cited by 183 publications

References 0 publications

Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions

Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions

Bimetallic Catalysis using Transition and Group 11 Metals: An Emerging Tool for CC Coupling and Other Reactions

Synthesis of Polycyclic Aromatic Hydrocarbon‐Based Nanovehicles Equipped with Triptycene Wheels

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