Multicomponent Synthesis of Unsymmetrical Unsaturated N‐Heterocyclic Carbene Precursors and Their Related Transition‐Metal Complexes

Queval, Pierre; Jahier, Claire; Rouen, Mathieu; Artur, Isabelle; Legeay, Jean Christophe; Falivene, Laura; Toupet, Loı̈c; Crévisy, Christophe; Cavallo, Luigi; Baslé, Olivier; Mauduit, Marc

doi:10.1002/anie.201308873

Cited by 74 publications

(47 citation statements)

References 45 publications

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“…This abnormal behavior should certainly be attributed to the special properties of the newly developed unsymmetrical NHC ligands. [8] Indeed, 1-aryl-3-cycloalkylimidazol-2-ylidenes combine strong electron richness with high steric discrimination between the flexible aliphatic and bulky aromatic groups. [9,10] Analysis of the maps reported in Figure 2 also indicated that the cyclododecyl fragment minimized the steric hindrance around the metal with a buried volume % (V bur ) of 29.7 relative to the classical IMes ligand, with a V bur of 31.3 ( Figure 2).…”

Section: Resultsmentioning

confidence: 99%

“…[7] With the aim of gaining rapid access to a wide variety of unsymmetrical NHC precursors, we recently developed a multicomponent methodology that afforded N,N'-disubstituted imidazolium salts in a single step. [8] Notably, this revisited strategy of Arduengo appeared extremely efficient in the scalable preparation of 1-aryl-3-cycloalkylimidazolium salts with excellent selectivity (up to 93 %), far beyond the expected 1:2:1 statistical ratio. As a representative example, 1-mesityl-3-cyclododecylimidazolium salt 1 was prepared with 93 % selectivity and 80 % yield on a 60 g scale.…”

Section: Introductionmentioning

confidence: 99%

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Cationic Bis‐N‐Heterocyclic Carbene (NHC) Ruthenium Complex: Structure and Application as Latent Catalyst in Olefin Metathesis

Rouen

Queval

Falivene

et al. 2014

Chemistry A European J

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An unexpected cationic bis-N-heterocyclic carbene (NHC) benzylidene ether based ruthenium complex (2 a) was prepared through the double incorporation of an unsymmetrical unsaturated N-heterocyclic carbene (U2 -NHC) ligand that bore an N-substituted cyclododecyl side chain. The isolation and full characterization (including X-ray diffraction studies) of key synthetic intermediates along with theoretical calculations allowed us to understand the mechanism of the overall cationization process. Finally, the newly developed complex 2 a displayed interesting latent behavior during ring-closing metathesis, which could be "switched on" under acidic conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cationic Bis‐N‐Heterocyclic Carbene (NHC) Ruthenium Complex: Structure and Application as Latent Catalyst in Olefin Metathesis

Rouen

Queval

Falivene

et al. 2014

Chemistry A European J

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“…Besides chiral amines, amino alcohols 29 were also utilized in the synthesis of C 2 -symmetric gold(I) complexes 34. The respective NHC precursors 33 were obtained via a one-pot protocol [39,75] and were subsequently transformed into gold complexes by the reaction with AuCl•SMe 2 in acetone, mediated by K 2 CO 3 . However, the yield was strictly dependent on the substituents.…”

Section: Cyclic C 2 -Symmetric Gold(i) Complexesmentioning

confidence: 99%

“…Catalysts 2019, 9, A straightforward approach to imidazolium salts 112 and gold(I) complexes 113 has recently been developed by Toste (Scheme 17) [74]. Implementing Baslé and Mauduit's protocol [39,75], the authors have prepared a series of C1-symmetric NHC precursors via an elegant one-pot protocol, directly from chiral β-amino alcohols 29, mesityl amine (110), glyoxal (30), and paraformaldehyde (31). The developed protocol includes two experimentally common steps.…”

Section: Scheme 10mentioning

confidence: 99%

Chiral N-heterocyclic Carbene Gold Complexes: Synthesis and Applications in Catalysis

Michalak

Kośnik

2019

Catalysts

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N-Heterocyclic carbenes have found many applications in modern metal catalysis, due to the formation of stable metal complexes, and organocatalysis. Among a myriad of N-heterocyclic carbene metal complexes, gold complexes have gained a lot of attention due to their unique propensity for the activation of carbon-carbon multiple bonds, allowing many useful transformations of alkynes, allenes, and alkenes, inaccessible by other metal complexes. The present review summarizes synthetic efforts towards the preparation of chiral N-heterocyclic gold(I) complexes exhibiting C 2 and C 1 symmetry, as well as their applications in enantioselective catalysis. Finally, the emerging area of rare gold(III) complexes and their preliminary usage in asymmetric catalysis is also presented. Scheme 3. The synthesis of a gold(I) complex from (R)-1-aminotetralin.An elegant approach to C2-symmetric gold(I) complexes was described by Czekelius et al. [72] (Scheme 4), inspired by previous Herrmann's work [73]. The synthetic approach involves chiral amines 24, readily available from the corresponding phenylacetic acid 22 via the Friedel-Crafts reaction of bromobenzene and fractional crystallization of the corresponding tartaric acid amine salt upon reductive amination. The resulting amine 24 was further formylated and subjected to Bischler-Napieralski cyclization to give 3-aryl-substituted dihydroisoquinoline 25. Subsequent reductive coupling afforded the basic diamine skeleton 26 into a single diastereomer, which appeared a perfect platform for structural ligand diversification via Suzuki coupling. The functionalized diamines 26 were then cyclized into imidazolium salts 27 with triethyl orthoformate to give the products with yields in the range of 49-94% (for selected examples, see Scheme 4). The formation of gold(I) complexes 28 was accomplished under rather unusual conditions, by the reaction of gold(I) chloride with a carbene generated by the action of KOtBu. Scheme 4. The synthesis of C2-symmetric gold(I) complexes accessible via a reductive coupling. The application of other chiral building blocks has recently been reported by the Toste group (Scheme 5) [74]. Besides chiral amines, amino alcohols 29 were also utilized in the synthesis of C2-Scheme 3. The synthesis of a gold(I) complex from (R)-1-aminotetralin.An elegant approach to C 2 -symmetric gold(I) complexes was described by Czekelius et al. [72] (Scheme 4), inspired by previous Herrmann's work [73]. The synthetic approach involves chiral amines 24, readily available from the corresponding phenylacetic acid 22 via the Friedel-Crafts reaction of bromobenzene and fractional crystallization of the corresponding tartaric acid amine salt upon reductive amination. The resulting amine 24 was further formylated and subjected to Bischler-Napieralski cyclization to give 3-aryl-substituted dihydroisoquinoline 25. Subsequent reductive coupling afforded the basic diamine skeleton 26 into a single diastereomer, which appeared a perfect platform for structural ligand diversification via Suzuki...

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“…Therefore, despite the efficiency contributed by the designed NHC-based catalyst 1, the development of a lower-cost catalyst appeared necessary to extend the validity of the technology to a large-scale process. Fortunately, during the course of this project, we developed a one-step multicomponent synthesis of unsaturated unsymmetrical NHC ligands bearing a cycloalkyl side chain 26 that could provide a cost-effective alternative to the multi-step synthe-sis of their saturated ligand analogues. Thanks to the potency of this ligand synthesis, catalysts 6 and 7 (bearing a cyclododecyl and a cyclopentyl moiety respectively) could be prepared 27 and evaluated in the self-metathesis reaction of 1octene under the standard conditions (Table 4).…”

Section: Table 1: Self-metathesis Of 1-octene Catalyzed By Complexes mentioning

confidence: 99%

Selective Metathesis of α-Olefins from Bio-Sourced Fischer–Tropsch Feeds

et al. 2016

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The search for a low-cost process for the valorization of linear α-olefins combining high productivity and high selectivity is a longstanding goal for chemists. Herein, we report a soluble ruthenium olefin metathesis catalyst that performs the conversion of linear α-olefins to longer internal linear olefins with high selectivity (>99%) under neat conditions at low loadings (50 ppm) and without the need of expensive additives. This robust catalytic process allowed us to efficiently and selectively re-equilibrate the naphtha fraction (C5–C8) of a Fischer–Tropsch feed derived from non-petroleum resources to a higher-value product range (C9–C14), useful as detergent and plasticizer precursorsThis work was supported by the European Community through the seventh framework program (CP-FP 211468-2 EUMET, grant to M.R., L.F., and E.B.). M.M. thanks the CNRS, the ENSCR, Rennes Métropole, and the Région-Bretagne for their financial support. A.P. thanks the Spanish MINECO for project CTQ2014- 59832-JIN, and L.C. acknowledges funding from the King Abdullah University of Science and Technology (KAUST

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Multicomponent Synthesis of Unsymmetrical Unsaturated N‐Heterocyclic Carbene Precursors and Their Related Transition‐Metal Complexes

Cited by 74 publications

References 45 publications

Cationic Bis‐N‐Heterocyclic Carbene (NHC) Ruthenium Complex: Structure and Application as Latent Catalyst in Olefin Metathesis

Cationic Bis‐N‐Heterocyclic Carbene (NHC) Ruthenium Complex: Structure and Application as Latent Catalyst in Olefin Metathesis

Chiral N-heterocyclic Carbene Gold Complexes: Synthesis and Applications in Catalysis

Selective Metathesis of α-Olefins from Bio-Sourced Fischer–Tropsch Feeds

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