Extension of the Alkane Bridge in BisNHC−Palladium−Chloride Complexes. Synthesis, Structure, and Catalytic Activity

Ahrens, Sebastian; Zeller, Alexander; Taige, Maria A.; Straßner, Thomas

doi:10.1021/om060577a

Cited by 184 publications

(88 citation statements)

References 47 publications

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“…[13b] 3, [22] 4, [23] 5, [24] 6, [25] 7 [26] and 8, [27] were prepared according to literature procedures. All solvents were used as received as technical grade solvents.…”

Section: Methodsmentioning

confidence: 99%

Alkyne Hydroarylations with Chelating Dicarbene Palladium(II) Complex Catalysts: Improved and Unexpected Reactivity Patterns Disclosed Upon Additive Screening

et al. 2009

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Palladium(II) complexes with a ligand set made from a chelating N-heterocyclic dicarbene ligand and two weakly coordinating anions (generally introduced in situ upon addition of 2 equiv. of a suitable silver salt) were found to be very active and selective catalysts for the room-temperature hydroarylation of alkynes at low catalyst loading (0.1 mol-%). Moreover, the screening of various strong acids as reaction promoters revealed that both the strength of the acid and the coordinating ability of its conjugated base influence the catalytic performance. Most remarkably, the use of HBF(4) together with a dicarbene Pd complex catalyst provides a dramatic change in the selectivity of the reaction, with the prevalent formation of a product stemming from the insertion of two molecules of alkyne into the aromatic C-H bond. The results presented herein highlight the fact that the dicarbene ligand, apart from stabilising the catalyst, is also able to enhance catalytic activity and, most notably, to steer the reaction selectivity towards novel products

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“…[13b] 3, [22] 4, [23] 5, [24] 6, [25] 7 [26] and 8, [27] were prepared according to literature procedures. All solvents were used as received as technical grade solvents.…”

Section: Methodsmentioning

confidence: 99%

Alkyne Hydroarylations with Chelating Dicarbene Palladium(II) Complex Catalysts: Improved and Unexpected Reactivity Patterns Disclosed Upon Additive Screening

et al. 2009

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“…Note, the use of a bis-imidazolium salt similar to 5 but with chloride counter-ions has been reported to afford a silver complex with a different dinuclear structure, with only one bridging dicarbene ligand and one chloride coordinated to each silver atom. [20] Complexes 3a-6a were employed as starting materials in the transmetallation reaction in which the NHC ligands were transferred from silver to copper to yield the complexes 3b-6b. Their spectroscopic data compare well with those of the previously reported, structurally characterised complex 3b [12,13] and also suggest for the novel complexes a dinuclear structure with two bridging dicarbene ligands.…”

Section: Synthesis Of Bis-carbene-silver and -Copper Complexesmentioning

confidence: 99%

Polynuclear Copper(I) Complexes with Chelating Bis‐ and Tris‐N‐Heterocyclic Carbene Ligands: Catalytic Activity in Nitrene and Carbene Transfer Reactions

et al. 2012

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Di- and trinuclear complexes of copper(I) bearing bis- or tris-N-heterocyclic carbene ligands have been prepared and evaluated as catalysts in nitrene transfer reactions from PhI=NTs to unsaturated and saturated substrates (olefin aziridination and C–H bond amidation) and carbene transfer reactions from diazo compounds to olefins. The complexes exhibited moderate-to-high catalytic activity in both processes. The tosylamidation of C–H bonds, previously unreported with a NHC-containing copper catalyst, was promoted by the dinuclear complexes

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“…The reagents were purchased by Aldrich as high-purity products and generally used as received. Complexes 2, [16] 4, [18] 5, [19] [b] In parentheses the yield in the hydrolysed product. Reaction conditions: see Experimental Section.…”

Section: Experimental Section General Remarksmentioning

confidence: 99%

Highly Efficient Alkyne Hydroarylation with Chelating Dicarbene Palladium(II) and Platinum(II) Complexes

et al. 2008

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We report on a novel reaction protocol for the coupling of arenes with alkynes (the Fujiwara reaction), yielding products of formal trans-hydroarylation of the triple bond. The protocol makes use of a chelating N-heterocyclic dicarbene palladium(II) complex as catalyst and allows us to perform the reaction in a few hours with only 0.1 mol % catalyst yielding the trans-hydroarylation product in high yields and with excellent selectivity. We discuss the applicability of this reaction protocol, which appears at present quite general with respect to the alkyne, albeit limited to electron-rich arenes. We also present the results of catalyst optimisation with respect to the nature of the nitrogen substituents in the carbene units, of the bridging group between the carbene units and of the coordinated anionic ligands. Finally, we also discuss the catalytic performance of a related chelating dicarbene complex of platinum(II).

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Extension of the Alkane Bridge in BisNHC−Palladium−Chloride Complexes. Synthesis, Structure, and Catalytic Activity

Cited by 184 publications

References 47 publications

Alkyne Hydroarylations with Chelating Dicarbene Palladium(II) Complex Catalysts: Improved and Unexpected Reactivity Patterns Disclosed Upon Additive Screening

Alkyne Hydroarylations with Chelating Dicarbene Palladium(II) Complex Catalysts: Improved and Unexpected Reactivity Patterns Disclosed Upon Additive Screening

Polynuclear Copper(I) Complexes with Chelating Bis‐ and Tris‐N‐Heterocyclic Carbene Ligands: Catalytic Activity in Nitrene and Carbene Transfer Reactions

Highly Efficient Alkyne Hydroarylation with Chelating Dicarbene Palladium(II) and Platinum(II) Complexes

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