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Athira C, Sreenithya A, Hadad CM, Sunoj RB. Cooperative Asymmetric Dual Catalysis Involving a Chiral N-Heterocyclic Carbene Organocatalyst and Palladium in an Annulation Reaction: Mechanism and Origin of Stereoselectivity. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- C. Athira
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - A. Sreenithya
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Christopher M. Hadad
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Alternating Ring-Opening Metathesis Polymerization Promoted by Ruthenium Catalysts Bearing Unsymmetrical NHC Ligands. Catalysts 2022. [DOI: 10.3390/catal13010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In this paper, Grubbs- and Hoveyda–Grubbs-type olefin metathesis catalysts featuring N-cyclopentyl/N’-mesityl backbone-substituted N-heterocyclic carbene (NHC) ligands were synthesized. Their propensity to promote the alternating ring-opening metathesis copolymerization (ROMP) of norbornene (NBE) with cyclooctene (COE) or cyclopentene (CPE) was evaluated and compared to that shown by analogous N-cyclohexyl complexes. High degrees of chemoselectivity were achieved in both copolymerizations. The presence of the N-cyclopentyl substituent allowed for the achievement of up to 98% and 97% of alternating diads for NBE-COE and NBE-CPE copolymers, respectively, at low comonomer ratios. Density functional theory (DFT) studies showed that both the sterical and electronic effects of NHC ligands influence catalyst selectivity.
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C2-Symmetric N-Heterocyclic Carbenes in Asymmetric Transition-Metal Catalysis. Symmetry (Basel) 2022. [DOI: 10.3390/sym14081615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The last decades have witnessed a rapid growth of applications of N-heterocyclic carbenes (NHCs) in different chemistry fields. Due to their unique steric and electronic properties, NHCs have become a powerful tool in coordination chemistry, allowing the preparation of stable metal-ligand frameworks with both main group metals and transition metals. An overview on the use of five membered monodentate C2-symmetric N-heterocyclic carbenes (NHCs) as ligands for transition-metal complexes and their most relevant applications in asymmetric catalysis is offered.
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Ma JB, Zhao X, Zhang D, Shi SL. Enantio- and Regioselective Ni-Catalyzed para-C-H Alkylation of Pyridines with Styrenes via Intermolecular Hydroarylation. J Am Chem Soc 2022; 144:13643-13651. [PMID: 35857884 DOI: 10.1021/jacs.2c04043] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Direct asymmetric functionalization of the pyridyl C-H bond represents a longstanding challenge in organic chemistry. We herein describe the first enantioselective para-C-H activation of pyridines through the use of a Ni-Al bimetallic catalyst system and N-heterocyclic carbene (NHC) ligand for intermolecular hydroarylation of styrenes. The reaction procceds in high to excellent enantioselectivities (up to 98.5:1.5 er) and high site-selectivities for both styrene and pyridine components (up to >98:2). Consequently, a broad range of enantioenriched 1,1-diarylalkanes containing pyridine moieties could be prepared in a single step with 100% atom economy. Computational studies supported a mechanism involving a ligand-to-ligand H-transfer (LLHT) and reductive elimination sequence, with LLHT being the rate- and enantioselectivity-determining step. DFT studies indicate that the π-π stacking interaction between the NHC aryl fragment and trans-styrenes is critical for high reactivity and enantiocontrol.
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Affiliation(s)
- Jun-Bao Ma
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Xia Zhao
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Dongju Zhang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Shi-Liang Shi
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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Ruamps M, Bastin S, Rechignat L, Sournia-Saquet A, Vendier L, Lugan N, Mouesca JM, Valyaev DA, Maurel V, César V. Redox-Switchable Behavior of Transition-Metal Complexes Supported by Amino-Decorated N-Heterocyclic Carbenes. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123776. [PMID: 35744903 PMCID: PMC9227367 DOI: 10.3390/molecules27123776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022]
Abstract
The coordination chemistry of the N-heterocyclic carbene ligand IMes(NMe2)2, derived from the well-known IMes ligand by substitution of the carbenic heterocycle with two dimethylamino groups, was investigated with d6 [Mn(I), Fe(II)], d8 [Rh(I)], and d10 [Cu(I)] transition-metal centers. The redox behavior of the resulting organometallic complexes was studied through a combined experimental/theoretical study, involving electrochemistry, EPR spectroscopy, and DFT calculations. While the complexes [CuCl(IMes(NMe2)2)], [RhCl(COD)(IMes(NMe2)2)], and [FeCp(CO)2 (IMes(NMe2)2)](BF4) exhibit two oxidation waves, the first oxidation wave is fully reversible but only for the first complex the second oxidation wave is reversible. The mono-oxidation event for these complexes occurs on the NHC ligand, with a spin density mainly located on the diaminoethylene NHC-backbone, and has a dramatic effect on the donating properties of the NHC ligand. Conversely, as the Mn(I) center in the complex [MnCp(CO)2 ((IMes(NMe2)2)] is easily oxidizable, the latter complex is first oxidized on the metal center to form the corresponding cationic Mn(II) complex, and the NHC ligand is oxidized in a second reversible oxidation wave.
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Affiliation(s)
- Mirko Ruamps
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Stéphanie Bastin
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Lionel Rechignat
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Alix Sournia-Saquet
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Laure Vendier
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Noël Lugan
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
| | - Jean-Marie Mouesca
- Université Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France;
| | - Dmitry A. Valyaev
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
- Correspondence: (D.A.V.); (V.M.); (V.C.)
| | - Vincent Maurel
- Université Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France;
- Correspondence: (D.A.V.); (V.M.); (V.C.)
| | - Vincent César
- LCC-CNRS, Université de Toulouse, CNRS, 31077 Toulouse, France; (M.R.); (S.B.); (L.R.); (A.S.-S.); (L.V.); (N.L.)
- Correspondence: (D.A.V.); (V.M.); (V.C.)
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Matsuki T, Teramoto H, Ichihara R, Inui K, Sakaguchi S. Asymmetric silane reduction of ketones and β-Keto esters catalyzed by a chiral azolium/iridium system in the presence of a base in methanol at room temperature. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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