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Xu L, Yang T, Sun H, Zeng J, Mu S, Zhang X, Chen GQ. Rhodium-Catalyzed Asymmetric Hydrogenation and Transfer Hydrogenation of 1,3-Dipolar Nitrones. Angew Chem Int Ed Engl 2024; 63:e202319662. [PMID: 38366812 DOI: 10.1002/anie.202319662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/03/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024]
Abstract
Owing to their distinctive 1,3-dipolar structure, the catalytic asymmetric hydrogenation of nitrones to hydroxylamines has been a formidable and longstanding challenge, characterized by intricate enantiocontrol and susceptibility to N-O bond cleavage. In this study, the asymmetric hydrogenation and transfer hydrogenation of nitrones were accomplished with a tethered TsDPEN-derived cyclopentadienyl rhodium(III) catalyst (TsDPEN: p-toluenesulfonyl-1,2-diphenylethylene-1,2-diamine), the reaction proceeds via a novel 7-membered cyclic transition state, producing chiral hydroxylamines with up to 99 % yield and >99 % ee. The practical viability of this methodology was underscored by gram-scale catalytic reactions and subsequent transformations. Furthermore, mechanistic investigations and DFT calculations were also conducted to elucidate the origin of enantioselectivity.
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Affiliation(s)
- Liren Xu
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Tilong Yang
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Hao Sun
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Jingwen Zeng
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Shuo Mu
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Xumu Zhang
- Department of Chemistry, the Grubbs Institute, and Medi-X Pingshan, Southern University of Science and Technology, Shenzhen, China
| | - Gen-Qiang Chen
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
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2
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Sarkar A, Dong G, Quaglia-Motta J, Sackett K. Flow-NMR as a Process-Monitoring Tool for mRNA IVT Reaction. J Pharm Sci 2024; 113:900-905. [PMID: 38008177 DOI: 10.1016/j.xphs.2023.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 11/28/2023]
Abstract
Messenger RNA (mRNA) based vaccines were instrumental in accelerating the end of the SARS-CoV-2 pandemic and are being aggressively developed as prophylaxes for a range of viral diseases. The swift adoption of mRNA-based therapeutics has also left open vast areas of opportunity for improving the development of mRNA-based drugs. One such area with immense potential focuses on the mRNA drug substance production, where mRNA is generated by a cell-free reaction called in vitro transcription (IVT). Process analytical technologies (PAT) are integral to the pharmaceutical industry and are necessary to facilitate agile process optimization and enhance process quality, control, and understanding. Due to the complexity and novelty inherent to the IVT reaction, there is a need for effective PAT that would provide in-depth, real-time insight into the reaction process to allow delivery of novel mRNA vaccines to patients faster in a more cost-effective way. Herein, we showcase the development of flow-nuclear magnetic resonance (flow-NMR) as a highly effective process-analytical tool for monitoring mRNA IVT reactions to support process development, optimization, and production.
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Affiliation(s)
- Aritra Sarkar
- Analytical Research and Development, Pfizer Research and Development, Eastern Point Road, Groton, CT 06340, United States of America.
| | - Guogang Dong
- Bioprocess Research and Development, Pfizer Research and Development, 1 Burtt Road, Andover, Massachusetts 01810, United States of America
| | - Jennifer Quaglia-Motta
- Bioprocess Research and Development, Pfizer Research and Development, 1 Burtt Road, Andover, Massachusetts 01810, United States of America
| | - Kelly Sackett
- Analytical Research and Development, Pfizer Research and Development, Eastern Point Road, Groton, CT 06340, United States of America.
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3
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Booth R, Whitwood AC, Duhme-Klair AK. Effect of Ligand Substituents on Spectroscopic and Catalytic Properties of Water-Compatible Cp*Ir-(pyridinylmethyl)sulfonamide-Based Transfer Hydrogenation Catalysts. Inorg Chem 2024; 63:3815-3823. [PMID: 38343274 PMCID: PMC10900292 DOI: 10.1021/acs.inorgchem.3c04040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/23/2024] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Transition-metal-based hydrogenation catalysts have applications ranging from high-value chemical synthesis to medicinal chemistry. A series of (pyridinylmethyl)sulfonamide ligands substituted with electron-withdrawing and -donating groups were synthesized to study the influence of the electronic contribution of the bidentate ligand in Cp*Ir piano-stool complexes. A variable-temperature NMR investigation revealed a strong correlation between the electron-donating ability of the substituent and the rate of stereoinversion of the complexes. This correlation was partially reflected in the catalytic activity of the corresponding catalysts. Complexes with electron-withdrawing substituents followed the trend observed in the variable-temperature NMR study, thereby confirming the rate-determining step to be donation of the hydride ligand. Strongly electron-donating groups, on the other hand, caused a change in the rate-determining step in the formation of the iridium-hydride species. These results demonstrate that the activity of these catalysts can be tuned systematically via changes in the electronic contribution of the bidentate (pyridinylmethyl)sulfonamide ligands.
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4
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Bara‐Estaún A, Harder MC, Lyall CL, Lowe JP, Suturina E, Hintermair U. Paramagnetic Relaxation Agents for Enhancing Temporal Resolution and Sensitivity in Multinuclear FlowNMR Spectroscopy. Chemistry 2023; 29:e202300215. [PMID: 36946535 PMCID: PMC10962566 DOI: 10.1002/chem.202300215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/22/2023] [Accepted: 03/22/2023] [Indexed: 03/23/2023]
Abstract
Sensitivity in FlowNMR spectroscopy for reaction monitoring often suffers from low levels of pre-magnetisation due to limited residence times of the sample in the magnetic field. While this in-flow effect is tolerable for high sensitivity nuclei such as 1 H and 19 F, it significantly reduces the signal-to-noise ratio in 31 P and 13 C spectra, making FlowNMR impractical for low sensititvity nuclei at low concentrations. Paramagnetic relaxation agents (PRAs), which enhance polarisation and spin-lattice relaxation, could eliminate the adverse in-flow effect and improve the signal-to-noise ratio. Herein, [Co(acac)3 ], [Mn(acac)3 ], [Fe(acac)3 ], [Cr(acac)3 ], [Ni(acac)2 ]3, [Gd(tmhd)3 ] and [Cr(tmhd)3 ] are investigated for their effectiveness in improving signal intensity per unit time in FlowNMR applications under the additional constraint of chemical inertness towards catalytically active transition metal complexes. High-spin Cr(III) acetylacetonates emerged as the most effective compounds, successfully reducing 31 P T1 values four- to five-fold at PRA concentrations as low as 10 mM without causing adverse line broadening. Whereas [Cr(acac)3 ] showed signs of chemical reactivity with a mixture of triphenylphosphine, triphenylphosphine oxide and triphenylphosphate over the course of several hours at 80° C, the bulkier [Cr(tmhd)3 ] was stable and equally effective as a PRA under these conditions. Compatibility with a range of representative transition metal complexes often used in homogeneous catalysis has been investigated, and application of [Cr(tmhd)3 ] in significantly improving 1 H and 31 P{1 H} FlowNMR data quality in a Rh-catalysed hydroformylation reaction has been demonstrated. With the PRA added, 13 C relaxation times were reduced more than six-fold, allowing quantitative reaction monitoring of substrate consumption and product formation by 13 C{1 H} FlowNMR spectroscopy at natural abundance.
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Affiliation(s)
- Alejandro Bara‐Estaún
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Marie C. Harder
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Catherine L. Lyall
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - John P. Lowe
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Elizaveta Suturina
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
| | - Ulrich Hintermair
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
- Institute for SustainabilityUniversity of BathBathBA2 7AYUnited Kingdom
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5
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Facchetti G, Neva F, Coffetti G, Rimoldi I. Chiral 8-Amino-5,6,7,8-tetrahydroquinoline Derivatives in Metal Catalysts for the Asymmetric Transfer Hydrogenation of 1-Aryl Substituted-3,4-dihydroisoquinolines as Alkaloids Precursors. Molecules 2023; 28:molecules28041907. [PMID: 36838894 PMCID: PMC9962878 DOI: 10.3390/molecules28041907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/13/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
Chiral diamines based on an 8-amino-5,6,7,8-tetrahydroquinoline backbone, known as CAMPY (L1), or the 2-methyl substituted analogue Me-CAMPY (L2) were employed as novel ligands in Cp* metal complexes for the ATH of a series of substituted dihydroisoquinolines (DHIQs), known for being key intermediates in the synthesis of biologically active alkaloids. Different metal-based complexes were evaluated in this kind of reaction, rhodium catalysts, C3 and C4, proving most effective both in terms of reactivity and enantioselectivity. Although modest enantiomeric excess values were obtained (up to 69% ee in the case of substrate I), a satisfactory quantitative conversion was successfully fulfilled even in the case of the most demanding hindered substrates when La(OTf)3 was used as beneficial additive, opening up the possibility for a rational design of novel chiral catalysts alternatives to the Noyori-Ikariya (arene)Ru(II)/TsDPEN catalyst.
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6
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Demidoff FC, Caleffi GS, Figueiredo M, Costa PRR. Ru(II)-Catalyzed Asymmetric Transfer Hydrogenation of Chalcones in Water: Application to the Enantioselective Synthesis of Flavans BW683C and Tephrowatsin E. J Org Chem 2022; 87:14208-14222. [PMID: 36251770 DOI: 10.1021/acs.joc.2c01733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The oxo-tethered-Ru(II) precatalyst promoted the one-pot C═C/C═O reduction of chalcones using sodium formate as the hydrogen source in water through asymmetric transfer hydrogenation. Twenty-seven 1,3-diarylpropan-1-ols were obtained in good to excellent yields (up to 96%) and enantiomeric purities (up to 98:2). Our data suggested that the enones are first reduced to the corresponding dihydrochalcones (1,4-selectivity) and then into 1,3-diarylpropan-1-ols (C═O reduction). The stereoelectronic effects of electron-donating and electron-withdrawing groups at the ortho, meta and para positions of both aromatic rings were evaluated. The 2-OH group at the B ring was well tolerated, allowing a straightforward enantioselective synthesis of two flavans through the Mitsunobu cyclization, the antiviral (S)-BW683C and the natural flavan (S)-tephrowatsin E.
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Affiliation(s)
- Felipe C Demidoff
- Laboratório de Química Bioorgânica (LQB), Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Bloco H, Cidade Universitária, 21.941-902 Rio de Janeiro, Brasil
| | - Guilherme S Caleffi
- Laboratório de Química Bioorgânica (LQB), Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Bloco H, Cidade Universitária, 21.941-902 Rio de Janeiro, Brasil
| | - Marcella Figueiredo
- Laboratório de Química Bioorgânica (LQB), Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Bloco H, Cidade Universitária, 21.941-902 Rio de Janeiro, Brasil
| | - Paulo R R Costa
- Laboratório de Química Bioorgânica (LQB), Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Bloco H, Cidade Universitária, 21.941-902 Rio de Janeiro, Brasil
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7
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Khamis N, Clarkson GJ, Wills M. Heterocycle-containing Noyori-Ikariya catalysts for asymmetric transfer hydrogenation of ketones. Dalton Trans 2022; 51:13462-13469. [PMID: 35994090 DOI: 10.1039/d2dt02411j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of a range of N-(heterocyclesulfonyl)-functionalised Noyori-Ikariya catalysts is described. The complexes were prepared through a short sequence from C2-symmetric 1,2-diphenylethylene-1,2-diamine (DPEN) and were characterised by a range of methods including X-ray crystallography. The complexes were active catalysts for the asymmetric transfer hydrogenation (ATH) of a range of acetophenone derivatives, giving products of high ee in most cases, with notably good results for ortho-substituted acetophenones.
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Affiliation(s)
- Noha Khamis
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK. .,Department of Chemistry, Faculty of science, University of Alexandria, Alexandria, Egypt
| | - Guy J Clarkson
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
| | - Martin Wills
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
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8
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Gradiski MV, Rennie BE, Lough AJ, Morris RH. Electronic insights into aminoquinoline-based PN HN ligands: protonation state dictates geometry while coordination environment dictates N-H acidity and bond strength. Dalton Trans 2022; 51:11241-11254. [PMID: 35731231 DOI: 10.1039/d2dt01556k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A variety of transition metal complexes bearing aminoquinoline PNHH'-R ligands R = Ph (L1H), Cy (L2H) and their amido analogues are reported for rhodium(I) ([Rh(L1H)(PPh3)]+1 and Rh(L1)(PPh3) 2), cobalt(II) (Co(L2)(Cl) 3), and iron(II) ([Fe(L1H)2]2+5, Fe(L1)26, and [Fe(C5Me5)(L1H)]PF67). The acid-base and redox properties of the amido complexes 2, 6, and their protio parent complexes 1, and 5 permit the determination of the pKa and bond dissociation free energy (BDFE) of their N-H bonds while the ligand scaffold is coordinated to metal centres of square planar and octahedral geometry, respectively. From relative concentrations obtained by the use of 31P{1H} NMR spectroscopy, a pKaTHF value of 14 is calculated for rhodium complex 1, 6.4 for iron complex 5, and 24 for iron complex 7. These data, when combined with elecrochemical potentials obtained via cyclic voltammetry, allow the calculations of BDFE values for the N-H bond of 69 kcal mol-1 for 1, and of 55 kcal mol-1 for 5.
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Affiliation(s)
- Matthew V Gradiski
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Benjamin E Rennie
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Alan J Lough
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Robert H Morris
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
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9
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Cotman AE, Dub PA, Sterle M, Lozinšek M, Dernovšek J, Zajec Ž, Zega A, Tomašič T, Cahard D. Catalytic Stereoconvergent Synthesis of Homochiral β-CF 3, β-SCF 3, and β-OCF 3 Benzylic Alcohols. ACS ORGANIC & INORGANIC AU 2022; 2:396-404. [PMID: 36217345 PMCID: PMC9542724 DOI: 10.1021/acsorginorgau.2c00019] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
We describe an efficient
catalytic strategy for enantio- and diastereoselective
synthesis of homochiral β-CF3, β-SCF3, and β-OCF3 benzylic alcohols. The approach is
based on dynamic kinetic resolution (DKR) with Noyori–Ikariya
asymmetric transfer hydrogenation leading to simultaneous construction
of two contiguous stereogenic centers with up to 99.9% ee, up to 99.9:0.1
dr, and up to 99% isolated yield. The origin of the stereoselectivity
and racemization mechanism of DKR is rationalized by density functional
theory calculations. Applicability of the previously inaccessible
chiral fluorinated alcohols obtained by this method in two directions
is further demonstrated: As building blocks for pharmaceuticals, illustrated
by the synthesis of heat shock protein 90 inhibitor with in vitro
anticancer activity, and in particular, needle-shaped crystals of
representative stereopure products that exhibit either elastic or
plastic flexibility, which opens the door to functional materials
based on mechanically responsive chiral molecular crystals.
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Affiliation(s)
- Andrej Emanuel Cotman
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Pavel A. Dub
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Maša Sterle
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Matic Lozinšek
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
| | - Jaka Dernovšek
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Živa Zajec
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Anamarija Zega
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Tihomir Tomašič
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia
| | - Dominique Cahard
- CNRS UMR 6014 COBRA, Normandie Université, 76821 Mont Saint Aignan, France
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10
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Zheng Y, Wills M. Asymmetric transfer hydrogenation of boronic acid pinacol ester (Bpin)-containing acetophenones. Org Biomol Chem 2022; 20:3742-3746. [PMID: 35438123 DOI: 10.1039/d2ob00569g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A series of Bpin-containing acetophenone derivatives were reduced by asymmetric transfer hydrogenation (ATH), using Noyori-Ikariya catalysts, with formic acid/triethylamine, to alcohols in high ee when the Bpin is in the para- or meta-position. Substrates containing ortho-Bpin groups were reduced in lower ee, with formation of a cyclic boron-containing group. The products were converted to substituted derivatives using Pd-catalysed coupling reactions. The results represent the first examples of ATH of Bpin-containing ketones.
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Affiliation(s)
- Ye Zheng
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
| | - Martin Wills
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
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11
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Khromova OV, Emelyanov MA, Smol'yakov AF, Fedyanin IV, Maleev VI, Larionov VA. Family of Well-Defined Chiral-at-Cobalt(III) Complexes as Metal-Templated Hydrogen-Bond-Donor Catalysts: Effect of Chirality at the Metal Center on the Stereochemical Outcome of the Reaction. Inorg Chem 2022; 61:5512-5523. [PMID: 35357165 DOI: 10.1021/acs.inorgchem.1c03927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A family of well-defined Λ- and Δ-diastereomeric octahedral cationic chiral-at-cobalt complexes were obtained by a simple two-step reaction of (R,R)-1,2-diaminocyclohexane, (R,R)-1,2-diphenylethylenediamine, or (S)-2-(aminomethyl)pyrrolidine and substituted salicylaldehydes with a cobalt(III) salt. It was observed for the first time that the use of an excess of cobalt(III) salt provides both the enantiopure Λ and Δ forms of the corresponding cobalt(III) complexes 1 and 2 in a ratio of diastereomers ranging from 1:1.6 to >20:1 (Λ/Δ) and in 31-95% combined yields. The obtained complexes were robust, air- and bench-stable, soluble in most of organic solvents, and insoluble in water. Through variation of the substituents in the phenyl ring of the salicylaldehyde moiety, it was shown that both steric and electronic effects of substituents have a significant impact on the formation of Λ and Δ isomers. Next, the efficacies of the enantiopure metal-templated complexes 1-3 were investigated in three benchmark asymmetric reactions in order to compare their catalytic activity. The chiral cobalt(III) complexes 1-3 were tested as enantioselective hydrogen-bond-donor catalysts in such important reactions as the Michael addition of the O'Donnell substrate to methyl acrylate, epoxidation of chalcone, and trimethylsilylcyanation of benzaldehyde. It was clearly demonstrated that the chirality at the cobalt center has an impact on the stereochemical outcome of the reactions. In particular, the Λ(R,R)-1 and Δ(R,R)-1 complexes acted as "pseudoenantiomeric" catalysts in the epoxidation and trimethylsilylcyanoation reactions, providing both enantiomers of the products with up to 57% enantiomeric excess.
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Affiliation(s)
- Olga V Khromova
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation
| | - Mikhail A Emelyanov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation
| | - Alexander F Smol'yakov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation.,Plekhanov Russian University of Economics, Stremyanny per. 36, Moscow 117997, Russian Federation
| | - Ivan V Fedyanin
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation.,Plekhanov Russian University of Economics, Stremyanny per. 36, Moscow 117997, Russian Federation
| | - Victor I Maleev
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation
| | - Vladimir A Larionov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS), Vavilov Str. 28, Moscow 119991, Russian Federation.,Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya Str. 6, Moscow 117198, Russian Federation
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12
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Stevens MA, Colebatch AL. Cooperative approaches in catalytic hydrogenation and dehydrogenation. Chem Soc Rev 2022; 51:1881-1898. [PMID: 35230366 DOI: 10.1039/d1cs01171e] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Metal-ligand cooperativity (MLC) is an established strategy for developing effective hydrogenation and dehydrogenation catalysts. Metal-metal cooperativity (MMC) in bimetallic complexes is not as well understood, and to date has had limited implementation in (de)hydrogenation. Herein we use (de)hydrogenation processes as a platform to examine modes of cooperativity, with a particular focus on catalytic mechanisms. We investigate how lessons learnt from the extensive development of metal-ligand cooperative catalysts can aid the ongoing development of metal-metal cooperative catalysts.
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Affiliation(s)
- Michael A Stevens
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Annie L Colebatch
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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13
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Tethered ruthenium(II) η6-arene complexes: assessing the potential of benzylic substituents to control metal-centred chirality, and applications in asymmetric transfer hydrogenations of ketones. J Organomet Chem 2022. [DOI: 10.1016/j.jorganchem.2021.122232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Mwansa JM, Stirling MJ, Sweeney G, Hanusek J, Váňa J, Page MI. Carboxamide substituted tetramethylcyclopentadiene - synthesis, characterisation and its iridium(III) complex catalysed reduction of imines. Dalton Trans 2022; 51:2696-2707. [PMID: 35088802 DOI: 10.1039/d2dt00149g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The novel dimeric iodo-iridium(III) complex, [Ir(Cp*CONMe2)I2]2, (Cp*CONMe2 = η5-N,N-2,3,4,5-hexamethylcyclopenta-2,4-diene carboxamide) bearing an amide moiety within the tetramethylcyclopentadiene ring, has been synthesised and characterised. The ligand Cp*CONMe2 is synthesised as two regioisomers, however the 2-substituted isomer exists as two distinguishable conformers due to restricted rotation about the amide carbonyl carbon and the ring carbon. The relative acidities of Cp*CONMe2 and Cp* are compared by their relative rates of H/D exchange. The iridium complex of N,N-2,3,4,5-hexamethylcyclopenta-2-4-diene carboxamide [IrCp*CONMe2] and (R,R)-1,2-diphenyl-N'-tosylethane-1,2-diamine ((R,R)-TsDPEN) has been evaluated in the transfer hydrogenation of imines under acidic conditions - a 5 : 2 molar ratio of formic acid : triethylamine as the hydride source for the transfer hydrogenation of 1-methyl-3,4-dihydroisoquinoline (DHIQ) and its 6,7-dimethoxy derivative in acetonitrile. A decreasing enantiomeric excess with reaction progress is attributed to different kinetic orders for formation of the two product amine enantiomers. The pseudo zero-order formation of the R-amine may be due to a pre-steady-state formation of the less stable form of the diastereomeric catalyst. By contrast, both enantiomeric amines from 1-fluorinated methyl DHIQs as substrates for reduction are formed by pseudo first-order processes.
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Affiliation(s)
- Joseph M Mwansa
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK.
| | | | - Gemma Sweeney
- University of Huddersfield, Queensgate, Huddersfield HD1 3DH
| | - Jiří Hanusek
- Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Studentska 573, CZ 532 10 Pardubice, The Czech Republic.
| | - Jiří Váňa
- Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Studentska 573, CZ 532 10 Pardubice, The Czech Republic.
| | - Michael I Page
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK.
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Bara-Estaun A, Lyall C, Lowe JP, Pringle PG, Kamer P, Franke R, Hintermair U. Mapping Catalyst Activation, Turnover Speciation and Deactivation in Rh/PPh3-catalysed Olefin Hydroformylation. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00312k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report new insights into the fate of the precious metal during hydroformylation catalysis of 1-hexene with Rh/PPh3 complexes using multi-nuclear operando FlowNMR spectroscopy. By applying selectively excited 1H and...
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Berry DBG, Clegg I, Codina A, Lyall CL, Lowe JP, Hintermair U. Convenient and accurate insight into solution-phase equilibria from FlowNMR titrations. REACT CHEM ENG 2022. [DOI: 10.1039/d2re00123c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solution phase titrations are made easy by multi-nuclear FlowNMR spectroscopy with automated, continuous titre addition to give accurate insights into Brønsted acid/base, hydrogen bonding, Lewis acid/base and metal/ligand binding equilibria under native conditions.
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Affiliation(s)
- Daniel B. G. Berry
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - Ian Clegg
- Bruker UK Ltd, Banner Lane, CV4 9GH Coventry, UK
| | - Anna Codina
- Bruker UK Ltd, Banner Lane, CV4 9GH Coventry, UK
| | - Catherine L. Lyall
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - John P. Lowe
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - Ulrich Hintermair
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Claverton Down, BA2 7AY Bath, UK
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