Efficient synthesis of bulky N-Heterocyclic carbene ligands for coinage metal complexes

Kim, Young-Suk; Kim, Yonghwi; Hur, Moon Young; Lee, Eunsung

doi:10.1016/j.jorganchem.2016.07.023

Cited by 40 publications

(21 citation statements)

References 47 publications

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“…[7] Thei midazo[1,5-a]pyridin-3-ylidene platform (IPy), first disclosed independently by the groups of Lassaletta and Glorius in 2005, [8] places the Rg roup at the C5 position in close proximity to the metal center as ac onsequence of the annelation of pyridinyl and imidazolyl rings ( Figure 1). [10] In line with our dual interests in the design of functionalized NHCs [11,12] and the development of new selective gold catalytic systems, [13] we report herein an ovel class of functionalized IPy ligands for Figure 1. [9] Interestingly,IPy-based ligands and related N-fused heterobicyclic carbenes were already coordinated to gold(I) and led to efficient catalytic species in some instances (complexes A-C, Figure 1).…”

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confidence: 67%

An Original L‐shape, Tunable N‐Heterocyclic Carbene Platform for Efficient Gold(I) Catalysis

et al. 2019

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The synthesis and characterization of original NHC ligands based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) scaffold functionalized with aflanking barbituric heterocycle is described as well as their use as tunable ligands for efficient gold-catalyzed CÀN, CÀO, and CÀCb ond formations.H igh activity,regio-, chemo-, and stereoselectivities are obtained for hydroelementation and domino processes,u nderlining the excellent performance (TONs and TOFs) of these IPy-based ligands in gold catalysis.The gold-catalyzed domino reactions of 1,6-enynes give rise to functionalizedh eterocycles in excellent isolated yields under mild conditions.T he efficiency of the NHC gold 5 Me complex is remarkable and mostly arises from acombination of steric protection and stabilization of the cationic Au I active species by ligand 1 Me . Scheme 2. Gold-catalyzed intermolecularaddition of amine and carboxylic acids to phenylacetylene and 1-dodecyne.Scheme 3. Au-catalyzed domino cyclization/nucleophilic addition of 1,6-enynesw ith various nucleophiles. [a] in CH 2 Cl 2 ;n .i. not isolated.

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confidence: 67%

An Original L‐shape, Tunable N‐Heterocyclic Carbene Platform for Efficient Gold(I) Catalysis

et al. 2019

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“…Therefore, we investigated the ability of NHC-based copper catalysts to promote the selective 1,6-conjugate addition reaction. Notably, a sterically demanding aryl-substituted Trip-Py-IPrCuCl catalyst [12] was found to be the most selective and efficient. [11] To our delight, when the reaction was carried out in the presence of IPrCuCl and KOt-Bu at 70°C for 15 h, pyrazole was added at the δ-position of diene 1, affording desired (E)-selective allylic amine product 3 a in 50% yield with 86:14 regioselectivity (3 a:4 b), albeit with the generation of 5% of (Z)-isomer 4 a, 3% of vinyl sulfone 4 c and 17% of diaminated product 4 d as the main side product (entries 1 and 2).…”

Section: Resultsmentioning

confidence: 99%

“…To improve the regioselectivity and stereoselectivity and suppress the diamination reaction, various NHCÀ CuCl catalysts were screened as illustrated in entries 3-7. Notably, a sterically demanding aryl-substituted Trip-Py-IPrCuCl catalyst [12] was found to be the most selective and efficient. When the 1,6-conjugate addition of pyrazole to 1 was carried out at 50°C in the presence of TripPy-IPrCuCl and KOt-Bu, the (E)allylic amine 3 a was obtained in 93% yield with > 98: < 2 regio-and stereoselectivities (entry 7).…”

Section: Resultsmentioning

confidence: 99%

Copper‐Catalyzed Regio‐ and Stereoselective 1,6‐Conjugate Addition of Aza‐Heterocycles to 1‐Sulfonyl‐1,3‐dienes

Park

Lee

2019

Adv Synth Catal

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An efficient and straightforward method for the synthesis of new and versatile sulfonylfunctionalized allylic amines through the selective copper-catalyzed aza-1,6-conjugate addition of heterocycles or arylamines to 1,4-disubstituted-1,3-dienyl sulfones has been developed. This catalytic process is promoted by a combination of an easily prepared and sterically demanding N-heterocyclic carbene-based copper complex and KOt-Bu under mild reaction conditions to provide a broad range of (E)-allylic amines with excellent regioand stereoselectivities.[a] Reaction conditions: sulfonyl diene 5 (0.36 mmol), pyrazole (2 a, 0.30 mmol), TripPy-IPrCuCl (7.5 mol %), KOt-Bu (7 mol %), toluene (1.0 M) under N 2 . In all cases, > 95: < 5 regio-and stereoselectivities were achieved. [b] Yields of the isolated products.Scheme 3. Synthetic transformations.

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“…Imidazo[1,5-a]pyridinium salts have recently attracted attention duet ot heir potential application as N-heterocyclic carbene precursors with tunable steric and electronic properties. [12] By utilizing such features, we describe herein the synthesis of the bulky tris-imidazo[1,5-a]pyridiniums alts H 3 -L(PF 6 ) 3 (L = 4a-4c;s ee Scheme 1) and their subsequent use in generating trinuclearA g I and Au I hexacarbene coordination cages. Not only do the cages feature as ignificantly larger cavity,b ut also al arger M···M separation compared with in the B-a nd Ctype cylindrical complexes,w hichi sb eneficialf or the inclusion of guest molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Not only do the cages feature as ignificantly larger cavity,b ut also al arger M···M separation compared with in the B-a nd Ctype cylindrical complexes,w hichi sb eneficialf or the inclusion of guest molecules. In addition, imidazo[1,5-a]pyridinium salts have rarely been used in discrete organometallic NHC-M com-plexes [12] and the metallosupramolecular assemblies derived from the imidazo[1,5-a]pyridinium salts prepared in this work are unprecedented.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Properties of Organometallic Molecular Cylinders Bearing Bulky Imidazo[1,5‐a]pyridine‐Based N‐Heterocyclic Carbene Ligands

Zhang

Das

et al. 2019

Chemistry A European J

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The metal-controlled self-assembly of organometallic molecular cylinders from as eries of imidazo[1,5-a]pyridine-based tris-NHCl igandsi sd escribed in this report. The imidazo[1,5-a]pyridinium salts H 3 -L(PF 6 ) 3 (L = 4a-4c)w ere treated with 1.5 equivalents of Ag 2 Ot oy ield the trinuclear Ag I hexacarbene cages [Ag 3 (L) 2 ](PF 6 ) 3 (L = 4a-4c), in which three Ag I are sandwiched between the two tricarbene ligands. The silver(I)c omplexes [Ag 3 (L) 2 ](PF 6 ) 3 underwent a facile transmetalation reactioni nt he presence of 3equiva-lents of [AuCl(tht)] (tht = tetrahydrothiophene) to furnish the trinuclearA u I cylinder-like cages [Au 3 (L) 2 ](PF 6 ) 3 (L = 4a-4c) withoutd estruction of the metallosupramolecular structure. The new hexacarbene assembliesf eature al arge cavity that can easily accommodate am olecule of dimethyl sulfoxidea s molecular guest. This is the first study of au nique "hostguest" system containing an organometallic cylinder-like cage derived exclusively from poly-NHC ligands.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.Scheme2.Preparation of the trinuclears ilver(I) hexacarbene complexesand their transmetalationtot rinuclear gold(I) hexacarbene complexes.

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Efficient synthesis of bulky N-Heterocyclic carbene ligands for coinage metal complexes

Cited by 40 publications

References 47 publications

An Original L‐shape, Tunable N‐Heterocyclic Carbene Platform for Efficient Gold(I) Catalysis

An Original L‐shape, Tunable N‐Heterocyclic Carbene Platform for Efficient Gold(I) Catalysis

Copper‐Catalyzed Regio‐ and Stereoselective 1,6‐Conjugate Addition of Aza‐Heterocycles to 1‐Sulfonyl‐1,3‐dienes

Synthesis, Characterization, and Properties of Organometallic Molecular Cylinders Bearing Bulky Imidazo[1,5‐a]pyridine‐Based N‐Heterocyclic Carbene Ligands

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