1
|
He P, Guan MH, Hu MY, Zhou YJ, Huang MY, Zhu SF. Iron-Catalyzed Allylic C(sp 3)-H Silylation: Spin-Crossover-Efficiency-Determined Chemoselectivity. Angew Chem Int Ed Engl 2024; 63:e202402044. [PMID: 38469657 DOI: 10.1002/anie.202402044] [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: 01/29/2024] [Revised: 02/29/2024] [Accepted: 03/11/2024] [Indexed: 03/13/2024]
Abstract
The nuanced role of spin effects remains a critical gap in designing proficient open-shell catalysts. This study elucidates an iron-catalyzed allylic C(sp3)-H silylation/alkyne hydrosilylation reaction, in which the spin state of the open-shell iron catalyst dictates the reaction kinetics and pathway. Specifically, spin crossover led to alkyne hydrosilylation, whereas spin conservation resulted in a novel allylic C(sp3)-H silylation reaction. This chemoselectivity, governed by the spin-crossover efficiency, reveals an unexpected dimension in spin effects and a first in the realm of transition-metal-catalyzed in situ silylation of allylic C(sp3)-H bonds, which had been previously inhibited by the heightened reactivity of alkenes in hydrosilylation reactions. Furthermore, this spin crossover can either accelerate or hinder the reaction at different stages within a single catalytic reaction, a phenomenon scarcely documented. Moreover, we identify a substrate-assisted C-H activation mechanism, a departure from known ligand-assisted processes, offering a fresh perspective on C-H activation strategies.
Collapse
Affiliation(s)
- Peng He
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Mu-Han Guan
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Meng-Yang Hu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Yuan-Jun Zhou
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Ming-Yao Huang
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Shou-Fei Zhu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, China
| |
Collapse
|
2
|
Cramer HH, Duchemin C, Kovel CB, Kim J, Pecoraro MV, Chirik PJ. Ligand Field Sensitive Spin Acceleration in the Iron-Catalyzed [2 + 2] Cycloaddition of Unactivated Alkenes and Dienes. J Am Chem Soc 2024; 146:9947-9956. [PMID: 38537152 DOI: 10.1021/jacs.4c00591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Redox-active pyridine(diimine) (PDI) iron catalysts promote the reversible [2 + 2] cycloaddition of alkenes and dienes to cyclobutane derivatives that have applications ranging from fuels to chemically recyclable polymers. Metallacycles were identified as key intermediates, and spin crossover from the singlet to the triplet surface was calculated to facilitate the reductive coupling step responsible for the formation of the four-membered ring. In this work, a series of sterically and electronically differentiated PDI ligands was studied for the [2 + 2] cycloaddition of ethylene and butadiene to vinylcyclobutane. Kinetic studies revealed that the fastest and slowest turnover were observed with equally electron-deficient supporting ligands that either feature phenyl-substituted imine carbon atoms (MeBPDI) or a pyrazine core (MePZDI). While the oxidative cyclization was comparatively slow for both catalysts, the rate of reductive coupling─determined by stoichiometric 13C2H4 labeling studies─correlated with the turnover frequencies. Two-state density functional theory studies and the distinct electronic structures of related (iPrBPDI) and (iPrPZDI) iron methyl complexes revealed significantly different ligand field strengths due to either diminished ligand σ-donation (MeBPDI) or promoted metal π-backbonding (MePZDI). Spin acceleration, leading to fast reductive coupling and catalytic turnover, was promoted in the case of the weaker ligand field and depends on both the nature and position of the electron-withdrawing group. This study provides strong evidence for the role of two-state reactivity in C(sp3)-C(sp3) bond formation and insights on how ligand design either promotes or inhibits spin acceleration in earth-abundant metal catalysis.
Collapse
Affiliation(s)
- Hanna H Cramer
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Coralie Duchemin
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Carli B Kovel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Matthew V Pecoraro
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
3
|
Raje S, Sheikh Mohammad T, de Ruiter G. A Neutral PC NHCP Co(I)-Me Pincer Complex as a Catalyst for N-Allylic Isomerization with a Broad Substrate Scope. J Org Chem 2024; 89:4319-4325. [PMID: 38520345 PMCID: PMC11002938 DOI: 10.1021/acs.joc.3c02349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 02/26/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
Earth-abundant-metal catalyzed double bond transposition offers a sustainable and atom-economical route toward the synthesis of internal alkenes. With an emphasis specifically on internal olefins and ethers, the isomerization of allylic amines has been particularly under represented in the literature. Herein, we report an efficient methodology for the selective isomerization of N-allylic organic compounds, including amines, amides, and imines. The reaction is catalyzed by a neutral PCNHCP cobalt(I) pincer complex and proceeds via a π-allyl mechanism. The isomerization occurs readily at 80-90 °C, and it is compatible with a wide variety of functional groups. The in situ formed enamines could additionally be used for a one-pot inverse-electron-demand Diels-Alder reaction to furnish a series of diversely substituted heterobiaryls, which is further discussed in this report.
Collapse
Affiliation(s)
- Sakthi Raje
- Schulich Faculty of Chemistry, Technion—Israel Institute of Technology, Technion City, 3200008 Haifa, Israel
| | - Tofayel Sheikh Mohammad
- Schulich Faculty of Chemistry, Technion—Israel Institute of Technology, Technion City, 3200008 Haifa, Israel
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion—Israel Institute of Technology, Technion City, 3200008 Haifa, Israel
| |
Collapse
|
4
|
Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
Collapse
Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
| |
Collapse
|
5
|
He P, Hu MY, Li JH, Qiao TZ, Lu YL, Zhu SF. Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation. Natl Sci Rev 2024; 11:nwad324. [PMID: 38314400 PMCID: PMC10837105 DOI: 10.1093/nsr/nwad324] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/07/2023] [Accepted: 11/06/2023] [Indexed: 02/06/2024] Open
Abstract
Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively, and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.
Collapse
Affiliation(s)
- Peng He
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Meng-Yang Hu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Jin-Hong Li
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Tian-Zhang Qiao
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Yi-Lin Lu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Shou-Fei Zhu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| |
Collapse
|
6
|
Gao Y, Smith JM. Enabling Nucleophilic Reactivity in High-Spin Fe(II) Imido Complexes: From Elementary Steps to Cooperative Catalysis. Acc Chem Res 2023; 56:3392-3403. [PMID: 37955993 DOI: 10.1021/acs.accounts.3c00511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
ConspectusTransition metal complexes featuring an M═NR bond have received great attention as critical intermediates in the synthesis of nitrogen-containing compounds. In general, the properties of the imido ligand in these complexes are dependent on the nature of the metal center. Thus, the imido ligand tends to be nucleophilic in early transition metal complexes and electrophilic in late transition metal complexes. Nonetheless, the supporting ligand can have a dramatic effect on its reactivity. For example, there are sporadic examples of nucleophilic late transition metal imido complexes, often based on strongly donating supporting ligands. Building on these earlier works, in this Article, we show that the imido ligand in a low-coordinate high-spin bis(carbene)borate Fe(II) complex is able to access previously unknown reaction pathways, ultimately leading to new catalytic transformations. We first focus on the synthesis, characterization, and stoichiometric reactivity of a highly nucleophilic Fe(II) imido complex. The entry point for this system is the intermediate-spin three-coordinate Fe(III) imido complex, which is generated from the reaction of an Fe(I) synthon with an organic azide. Alkali metal reduction leads to a series of M+ (M = Li, Na, K) coordinated and charge-separated (M = K(18-C-6)) high-spin Fe(II) imido complexes, all of which have been isolated and fully characterized. Combined with the electronic structure calculations, these results reveal that the alkali ions moderately polarize the Fe═N bond according to K+ ≈ Na+ < Li+. As a result, the basicity of the imido ligand increases from the charged separated complex to K+, Na+, and Li+ coordinated complexes, as validated by intermolecular proton transfer equilibria. The impact of the counterion on imido ligand reactivity is demonstrated through protonation, alkylation, and hydrogen atom abstraction reactions. The counterion also directs the outcome of [2 + 2] reactions with benzophenone, where alkali coordination facilitates double bond metathesis. Building from here, we describe how the unusual nucleophilicity of the high-spin Fe(II) imido complex revealed in stoichiometric reactions can be extended to new catalytic transformations. For example, a [2 + 2] cycloaddition reaction serves as the basis for the catalytic guanylation of carbodiimides under mild conditions. More interestingly, this complex also exhibits the first ene-like reactivity of an M═NR bond in reactions with alkynes, nitriles, and alkenes. These transformations form the basis of catalytic alkyne and nitrile α-deuteration and pKa-dictated alkene transposition reactions, respectively. Mechanistic studies reveal the critical role of metal-ligand cooperativity in facilitating these catalytic transformations and suggest the new avenues for transition metal imido complexes in catalysis that extend beyond classical nitrene transfer chemistry.
Collapse
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| |
Collapse
|
7
|
Bhutto SM, Hooper RX, Mercado BQ, Holland PL. Mechanism of Nitrogen-Carbon Bond Formation from Iron(IV) Disilylhydrazido Intermediates during N 2 Reduction. J Am Chem Soc 2023; 145:4626-4637. [PMID: 36794981 DOI: 10.1021/jacs.2c12382] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We recently reported a reaction sequence that activates C-H bonds in simple arenes as well as the N-N triple bond in N2, delivering the aryl group to N2 to form a new N-C bond (Nature 2020, 584, 221). This enables the transformation of abundant feedstocks (arenes and N2) into N-containing organic compounds. The key N-C bond forming step occurs upon partial silylation of N2. However, the pathway through which reduction, silylation, and migration occurred was unknown. Here, we describe synthetic, structural, magnetic, spectroscopic, kinetic, and computational studies that elucidate the steps of this transformation. N2 must be silylated twice at the distal N atom before aryl migration can occur, and sequential silyl radical and silyl cation addition is a kinetically competent pathway to a formally iron(IV)-NN(SiMe3)2 intermediate that can be isolated at low temperature. Kinetic studies show its first-order conversion to the migrated product, and DFT calculations indicate a concerted transition state for migration. The electronic structure of the formally iron(IV) intermediate is examined using DFT and CASSCF calculations, which reveal contributions from iron(II) and iron(III) resonance forms with oxidized NNSi2 ligands. The depletion of electron density from the Fe-coordinated N atom makes it electrophilic enough to accept the incoming aryl group. This new pathway for the N-C bond formation offers a method for functionalizing N2 using organometallic chemistry.
Collapse
Affiliation(s)
- Samuel M Bhutto
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Reagan X Hooper
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, United States
| |
Collapse
|
8
|
McWilliams SF, Mercado BQ, MacLeod KC, Fataftah MS, Tarrago M, Wang X, Bill E, Ye S, Holland PL. Dynamic effects on ligand field from rapid hydride motion in an iron(ii) dimer with an S = 3 ground state. Chem Sci 2023; 14:2303-2312. [PMID: 36873832 PMCID: PMC9977447 DOI: 10.1039/d2sc06412j] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023] Open
Abstract
Hydride complexes are important in catalysis and in iron-sulfur enzymes like nitrogenase, but the impact of hydride mobility on local iron spin states has been underexplored. We describe studies of a dimeric diiron(ii) hydride complex using X-ray and neutron crystallography, Mössbauer spectroscopy, magnetism, DFT, and ab initio calculations, which give insight into the dynamics and the electronic structure brought about by the hydrides. The two iron sites in the dimer have differing square-planar (intermediate-spin) and tetrahedral (high-spin) iron geometries, which are distinguished only by the hydride positions. These are strongly coupled to give an S total = 3 ground state with substantial magnetic anisotropy, and the merits of both localized and delocalized spin models are discussed. The dynamic nature of the sites is dependent on crystal packing, as shown by changes during a phase transformation that occurs near 160 K. The change in dynamics of the hydride motion leads to insight into its influence on the electronic structure. The accumulated data indicate that the two sites can trade geometries by rotating the hydrides, at a rate that is rapid above the phase transition temperature but slow below it. This small movement of the hydrides causes large changes in the ligand field because they are strong-field ligands. This suggests that hydrides could be useful in catalysis not only due to their reactivity, but also due to their ability to rapidly modulate the local electronic structure and spin states at metal sites.
Collapse
Affiliation(s)
| | | | - K Cory MacLeod
- Department of Chemistry, Yale University New Haven Connecticut USA
| | - Majed S Fataftah
- Department of Chemistry, Yale University New Haven Connecticut USA
| | - Maxime Tarrago
- Max Planck Institute for Chemical Energy Conversion Mülheim an der Ruhr Germany
| | - Xiaoping Wang
- Neutron Sciences Directorate, Oak Ridge National Laboratory Oak Ridge Tennessee USA
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion Mülheim an der Ruhr Germany
| | - Shengfa Ye
- Max Planck Institute for Chemical Energy Conversion Mülheim an der Ruhr Germany
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian China
| | | |
Collapse
|
9
|
Brown AC, Suess DLM. Valence Localization in Alkyne and Alkene Adducts of Synthetic [Fe 4S 4] + Clusters. Inorg Chem 2023; 62:1911-1918. [PMID: 35704768 PMCID: PMC9751231 DOI: 10.1021/acs.inorgchem.2c01353] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Reported herein are alkyne and alkene adducts of synthetic [Fe4S4]+ clusters that model intermediates and inhibitor-bound states in enzymes involved in isoprenoid biosynthesis. Treatment of the N-heterocyclic carbene-ligated cluster [(IMes)3Fe4S4(OEt2)][BArF4] (IMes = 1,3-dimesitylimidazol-2-ylidene; [BArF4]- = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) with phenylacetylene (PhCCH) or cis-cyclooctene (COE) results in displacement of the Et2O ligand to yield the corresponding π complexes, [(IMes)3Fe4S4(PhCCH)][BArF4] and [(IMes)3Fe4S4(COE)][BArF4]. EPR spectroscopic analysis demonstrates that both clusters are doublets with giso > 2 and thus are spectroscopically faithful models of the analogous species characterized in the isoprenoid biosynthetic enzymes IspG and IspH. Structural and Mössbauer spectroscopic analysis reveals that both complexes are best described as [Fe4S4]+ clusters in which the unique Fe site engages in modest back-bonding to the π-acidic ligand. Paramagnetic NMR studies show that, even at room temperature, the alkyne/alkene-bound Fe centers harbor minority spin and therefore adopt an Fe2+ valence. We propose that such valence localization could likewise occur in Fe-S enzymes that interact with π-acidic molecules.
Collapse
|
10
|
Su S, Wu T, Xia Y, Wink DJ, Lee D. Cycloisomerization of Alkyne-Tethered N-Acyloxycarbamates to 2-(3H)Oxazolones through Nitrenoid-Mediated Carboxyamidation. Chemistry 2023; 29:e202203371. [PMID: 36628950 DOI: 10.1002/chem.202203371] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/12/2023]
Abstract
The cycloisomerization of alkyne-tethered N-benzoyloxycarbamates to 2-(3H)oxazolones is described. Two catalytic systems are tailored for intramolecular 5-exo-alkyne carboxyamidation and concomitant alkene isomerization. PtCl2 /CO (5 mol%, toluene, 100 °C) promotes both carboxyamidation and alkene isomerization but has a limited substrate scope. On the other hand, FeCl3 (5 mol%, CH3 CN, 100 °C) promotes carboxyamidation effectively but a cocatalyst is required for the exocyclic alkene isomerization. Thus, a two-step one-pot protocol has been developed for a broader reaction scope, which involves FeCl3 -catalyzed carboxyamidation and base-induced alkene isomerization. Crossover experiments suggest that these reactions proceed mainly through a mechanism involving acylnitrenoid intermediates rather than carbenoid intermediates.
Collapse
Affiliation(s)
- Siyuan Su
- Department of Chemistry, University of Illinois Chicago, 845 W. Taylor St., Chicago, Illinois, 60607, USA
| | - Tongtong Wu
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang Province, 325035, P. R. China
| | - Yuanzhi Xia
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang Province, 325035, P. R. China
| | - Donald J Wink
- Department of Chemistry, University of Illinois Chicago, 845 W. Taylor St., Chicago, Illinois, 60607, USA
| | - Daesung Lee
- Department of Chemistry, University of Illinois Chicago, 845 W. Taylor St., Chicago, Illinois, 60607, USA
| |
Collapse
|
11
|
Karagiannis A, Goel B, Prokopchuk DE. Putting a new spin on imido chemistry with an FeII dicarbene complex. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
12
|
Murakami T, Takayanagi T. Triplet-quintet spin-crossover efficiency in β-hydrogen transfer between Fe(C2H5)+ and HFe(C2H4)+. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
13
|
Gao Y, Pink M, Carta V, Smith JM. Ene Reactivity of an Fe═NR Bond Enables the Catalytic α-Deuteration of Nitriles and Alkynes. J Am Chem Soc 2022; 144:17165-17172. [PMID: 36070477 DOI: 10.1021/jacs.2c07462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herein, we report the reactions of an Fe(II) imido complex [Ph2B(tBuIm)2Fe═NDipp]- (1) with internal alkynes and isobutyronitrile, affording the Fe amido allenyl complexes [Ph2B(tBuIm)2Fe(NHDipp)((R1)C═C═C(R2)(H))]- (R1 = Et or nPr; R2 = Me or Et, 2-5) and the Fe amido keteniminate complex [Ph2B(tBuIm)2Fe(NHDipp)(N═C═CMe2)K(THF)]n (8-K), respectively. These transformations represent the previously unknown ene-like reactivity of a metal-ligand multiple bond. Stoichiometric reactions of 2 and 8-K with DippNH2 lead to the regeneration of 3-hexyne and isobutyronitrile, respectively, with concomitant formation of the bis(anilido) complex [Ph2B(tBuIm)2Fe(NHDipp)2]- (9). These results provide the platform for 1 as an efficient catalyst for the selective α-deuteration of nitriles and alkynes by RND2. These results demonstrate a new reaction mode for metal imido complexes and suggest new avenues for using the imido ligand in catalysis.
Collapse
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Veronica Carta
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| |
Collapse
|
14
|
Mirzanejad A, Varganov SA. The role of the intermediate triplet state in iron-catalyzed multi-state C-H activation. Phys Chem Chem Phys 2022; 24:20721-20727. [PMID: 36018581 DOI: 10.1039/d2cp02733j] [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
Efficient activation and functionalization of the C-H bond under mild conditions are of a great interest in chemical synthesis. We investigate the previously proposed spin-accelerated activation of the C(sp2)-H bond by a Fe(II)-based catalyst to clarify the role of the intermediate triplet state in the reaction mechanism. High-level electronic structure calculations on a small model of a catalytic system utilizing the coupled cluster with the single, double, and perturbative triple excitations [CCSD(T)] are used to select the density functional for the full-size model. Our analysis indicates that the previously proposed two-state quintet-singlet reaction pathway is unlikely to be efficient due to a very weak spin-orbit coupling between these two spin states. We propose a more favorable multi-state quintet-triplet-singlet reaction pathway and discuss the importance of the intermediate triplet state. This triplet state facilitates a spin-accelerated reaction mechanism by strongly coupling to both quintet and singlet states. Our calculations show that the C-H bond activation through the proposed quintet-triplet-singlet reaction pathway is more thermodynamically favorable than the single-state quintet and two-state singlet-quintet mechanisms.
Collapse
Affiliation(s)
- Amir Mirzanejad
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557-0216, USA.
| | - Sergey A Varganov
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557-0216, USA.
| |
Collapse
|
15
|
Parts-per-million of ruthenium catalyze the selective chain-walking reaction of terminal alkenes. Nat Commun 2022; 13:2831. [PMID: 35595741 PMCID: PMC9123009 DOI: 10.1038/s41467-022-30320-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 04/26/2022] [Indexed: 11/22/2022] Open
Abstract
The chain–walking of terminal alkenes (also called migration or isomerization reaction) is currently carried out in industry with unselective and relatively costly processes, to give mixtures of alkenes with significant amounts of oligomerized, branched and reduced by–products. Here, it is shown that part–per–million amounts of a variety of commercially available and in–house made ruthenium compounds, supported or not, transform into an extremely active catalyst for the regioselective migration of terminal alkenes to internal positions, with yields and selectivity up to >99% and without any solvent, ligand, additive or protecting atmosphere required, but only heating at temperatures >150 °C. The resulting internal alkene can be prepared in kilogram quantities, ready to be used in nine different organic reactions without any further treatment. The chain-walking of terminal alkenes is an industrially relevant reaction. Here, the authors show that part-per-million amounts of a variety of ruthenium compounds catalyze the reaction in yields and selectivity up to >99%, without any solvent or additive.
Collapse
|
16
|
Lin X, Mo Y. Partial Double Metal-Carbon Bonding Model in Transition Metal Methyl Compounds. Inorg Chem 2022; 61:2892-2902. [PMID: 35104122 DOI: 10.1021/acs.inorgchem.1c03619] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chemical bond between a transition metal and a methyl group (M-CH3) is typically defined as a single covalent bond, which is of fundamental significance and general interest in understanding the structural properties and reactivity of transition metal alkyl compounds. Herein, we demonstrate that the M-CH3 bonding involves varying σ and π components and thus should be best described in terms of the partial double M═CH3 bond. The often-neglected π bonding stems from an occupied π-symmetric orbital of the methyl group comprising all three C-H σ bonds (but one C-H' contributes more than the other two) and a vacant low-lying metal d(π) orbital, and is associated with the intramolecular C-H'···M agostic effect (i.e., an acute M-C-H' angle and a short H'···M distance), whose origin is still controversial. We quantify the geometric and energetic impacts of the π interaction involved in the M-CH3 bond by explicitly computing the intramolecular πCH' → dM interaction with the ab initio valence bond (VB) theory. Our computations of the ligand-free [TiCH3]3+ and a series of metallocene catalysts provide a direct proof for the presence of the π bonding in M-CH3 bonds, which is the cause for the agostic effect. The partial double M═CH3 bonding model is not only validated by a range of bonding analyses including VB self-consistent field (VBSCF)-based energy decomposition and quantum theory of atoms in molecules (QTAIM) but also authenticated by the specific activity of double M═CH3 bonds in the C-H activation and olefin insertion. More importantly, the σ bond gradually switches from a classical covalent bond to a novel charge-shift bond with the π bonding becoming increasingly significant. We anticipate that the recognition of the π interaction between electrophilic metal centers and C-H bonds can benefit the understanding of the nature of metal-carbon bonds in transition metal ethyl, alkyl, and carbene compounds.
Collapse
Affiliation(s)
- Xuhui Lin
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Yirong Mo
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
| |
Collapse
|
17
|
Lewis TWR, Mastin EM, Theis ZC, Gutierrez MG, Bellert DJ. Measurement of time dependent product branching ratios indicates two-state reactivity in metal mediated chemical reactions. Phys Chem Chem Phys 2022; 24:2300-2308. [PMID: 35015007 DOI: 10.1039/d1cp05473b] [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
For several decades, the influence of Two State Reactivity (TSR) has been implicated in a host of reactions, but has lacked a stand-alone, definitive experimental kinetic signature identifying its occurrence. Here, we demonstrate that the measurement of a temporally dependent product branching ratio is indicative of spin inversion and is a kinetic signature of TSR. This is caused by products exiting different hypersurfaces with different rates and relative exothermicities. The composite measurement of product intensities with the same mass but with different multiplicities yield biexponential temporal dependences with the sampled product ratio changing in time. These measurements are made using the single photon initiated dissociative rearrangement reaction (SPIDRR) technique which identifies TSR but further determines the kinetic parameters for reaction along the original ground electronic surface in competition with spin inversion and its consequent TSR.
Collapse
Affiliation(s)
- Tucker W R Lewis
- Department of Chemistry and Biochemistry, Baylor University, Darrin Bellert, One Bear Place #97348, Waco, TX 76798, USA
| | - Evan M Mastin
- Department of Chemistry and Biochemistry, Baylor University, Darrin Bellert, One Bear Place #97348, Waco, TX 76798, USA
| | - Zachry C Theis
- Department of Chemistry and Biochemistry, Baylor University, Darrin Bellert, One Bear Place #97348, Waco, TX 76798, USA
| | - Michael G Gutierrez
- Department of Chemistry and Biochemistry, Baylor University, Darrin Bellert, One Bear Place #97348, Waco, TX 76798, USA
| | - Darrin J Bellert
- Department of Chemistry and Biochemistry, Baylor University, Darrin Bellert, One Bear Place #97348, Waco, TX 76798, USA
| |
Collapse
|
18
|
Gao Y, Pink M, Smith JM. Alkali Metal Ions Dictate the Structure and Reactivity of an Iron(II) Imido Complex. J Am Chem Soc 2022; 144:1786-1794. [DOI: 10.1021/jacs.1c11429] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M. Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| |
Collapse
|
19
|
Skubi KL, Hooper RX, Mercado BQ, Bollmeyer MM, MacMillan SN, Lancaster KM, Holland PL. Iron Complexes of a Proton-Responsive SCS Pincer Ligand with a Sensitive Electronic Structure. Inorg Chem 2022; 61:1644-1658. [PMID: 34986307 PMCID: PMC8792349 DOI: 10.1021/acs.inorgchem.1c03499] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sulfur/carbon/sulfur pincer ligands have an interesting combination of strong-field and weak-field donors, a coordination environment that is also present in the nitrogenase active site. Here, we explore the electronic structures of iron(II) and iron(III) complexes with such a pincer ligand, bearing a monodentate phosphine, thiolate S donor, amide N donor, ammonia, or CO. The ligand scaffold features a proton-responsive thioamide site, and the protonation state of the ligand greatly influences the reduction potential of iron in the phosphine complex. The N-H bond dissociation free energy, derived from the Bordwell equation, is 56 ± 2 kcal/mol. Electron paramagnetic resonance (EPR) spectroscopy and superconducting quantum interference device (SQUID) magnetometry measurements show that the iron(III) complexes with S and N as the fourth donors have an intermediate spin (S = 3/2) ground state with a large zero field splitting, and X-ray absorption spectra show a high Fe-S covalency. The Mössbauer spectrum changes drastically with the position of a nearby alkali metal cation in the iron(III) amido complex, and density functional theory calculations explain this phenomenon through a change between having the doubly occupied orbital as dz2 or dyz, as the former is more influenced by the nearby positive charge.
Collapse
Affiliation(s)
- Kazimer L. Skubi
- Department of Chemistry, Yale University, New Haven, Connecticut 06511
| | - Reagan X. Hooper
- Department of Chemistry, Yale University, New Haven, Connecticut 06511
| | | | - Melissa M. Bollmeyer
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | | |
Collapse
|
20
|
Kamitani M. Chemically robust and readily available quinoline-based PNN iron complexes: application in C-H borylation of arenes. Chem Commun (Camb) 2021; 57:13246-13258. [PMID: 34812447 DOI: 10.1039/d1cc04877e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Iron catalysts have been used for over a century to produce ammonia industrially. However, the use of iron catalysts generally remained quite limited until relatively recently, when the abundance and low toxicity of iron spurred the development of a variety of iron catalysts. Despite the fact that iron catalysts are being developed as alternatives to precious metal catalysts, their reactivities and stabilities are quite different because of their unique electronic structures. In this context, our group previously developed a new family of quinoline-based PNN pincer-type ligands for low- to mid-valent iron catalysts. These chemically robust PNN ligands provide air- and moisture-tolerant iron complexes, which exhibit excellent catalytic performances in the C-H borylation of arenes. This feature article summarises our recent work on PNN iron complexes, including their conception and design, as well as related reports on iron pincer complexes and iron-catalysed C-H borylation reactions.
Collapse
Affiliation(s)
- Masahiro Kamitani
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0373, Japan.
| |
Collapse
|
21
|
Hakey BM, Leary DC, Rodriguez JG, Martinez JC, Vaughan NB, Darmon JM, Akhmedov NG, Petersen JL, Dolinar BS, Milsmann C. Effects of 2,6‐Dichlorophenyl Substituents on the Coordination Chemistry of Pyridine Dipyrrolide Iron Complexes. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Brett M. Hakey
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Dylan C. Leary
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jose G. Rodriguez
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jordan C. Martinez
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Nicholas B. Vaughan
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | | | - Novruz G. Akhmedov
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Brian S. Dolinar
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| |
Collapse
|
22
|
Liu J, Wu P, Yan S, Li Y, Cao Z, Wang B. Spin-Regulated Inner-Sphere Electron Transfer Enables Efficient O—O Bond Activation in Nonheme Diiron Monooxygenase MIOX. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jia Liu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Peng Wu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Shengheng Yan
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Yuanyuan Li
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, China
| | - Zexing Cao
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Binju Wang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| |
Collapse
|
23
|
Gao Y, Carta V, Pink M, Smith JM. Catalytic Carbodiimide Guanylation by a Nucleophilic, High Spin Iron(II) Imido Complex. J Am Chem Soc 2021; 143:5324-5329. [PMID: 33793235 DOI: 10.1021/jacs.1c02068] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reduction of the three-coordinate iron(III) imido [Ph2B(tBuIm)2Fe═NDipp] (1) affords [Ph2B(tBuIm)2Fe═NDipp][K(18-C-6)THF2] (2), a rare example of a high-spin (S = 2) iron(II) imido complex. Unusually for a late metal imido complex, the imido ligand in 2 has nucleophilic character, as demonstrated by the reaction with DippNH2, which establishes an equilibrium with the bis(anilido) complex [Ph2B(tBuIm)2Fe(NHDipp)2][K(18-C-6)THF2] (3). In an unusual transformation, formal insertion of iPrN═C═NiPr into the Fe═N(imido) bond yields the guanidinate [Ph2B(tBuIm)2Fe(iPrN)2CNDipp][K(18-C-6)THF2] (4). Reaction of 4 with excess DippNH2 provides 3, along with the guanidine (iPrNH)2C═NDipp. As suggested by these stoichiometric reactions, 2 is an efficient catalyst for the guanylation of carbodiimides, converting a wide range of aniline substrates under mild conditions.
Collapse
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Veronica Carta
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| |
Collapse
|
24
|
Woof CR, Durand DJ, Fey N, Richards E, Webster RL. Iron Catalyzed Double Bond Isomerization: Evidence for an Fe I /Fe III Catalytic Cycle. Chemistry 2021; 27:5972-5977. [PMID: 33492679 PMCID: PMC8048803 DOI: 10.1002/chem.202004980] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/19/2021] [Indexed: 12/21/2022]
Abstract
Iron-catalyzed isomerization of alkenes is reported using an iron(II) β-diketiminate pre-catalyst. The reaction proceeds with a catalytic amount of a hydride source, such as pinacol borane (HBpin) or ammonia borane (H3 N⋅BH3 ). Reactivity with both allyl arenes and aliphatic alkenes has been studied. The catalytic mechanism was investigated by a variety of means, including deuteration studies, Density Functional Theory (DFT) and Electron Paramagnetic Resonance (EPR) spectroscopy. The data obtained support a pre-catalyst activation step that gives access to an η2 -coordinated alkene FeI complex, followed by oxidative addition of the alkene to give an FeIII intermediate, which then undergoes reductive elimination to allow release of the isomerization product.
Collapse
Affiliation(s)
- Callum R. Woof
- School of ChemistryUniversity of BathClaverton DownBathBA2 7AYUK
| | - Derek J. Durand
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Natalie Fey
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Emma Richards
- School of ChemistryCardiff UniversityMain Building, Park PlaceCardiffCF10 3ATUK
| | - Ruth L. Webster
- School of ChemistryUniversity of BathClaverton DownBathBA2 7AYUK
| |
Collapse
|
25
|
Kim D, Pillon G, DiPrimio DJ, Holland PL. Highly Z-Selective Double Bond Transposition in Simple Alkenes and Allylarenes through a Spin-Accelerated Allyl Mechanism. J Am Chem Soc 2021; 143:3070-3074. [DOI: 10.1021/jacs.1c00856] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Daniel Kim
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Guy Pillon
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Daniel J. DiPrimio
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| |
Collapse
|
26
|
Gao Y, Pink M, Smith JM. Iron(II) Complexes of an Anionic Bis(ylide)diphenylborate Ligand. Inorg Chem 2020; 59:17303-17309. [DOI: 10.1021/acs.inorgchem.0c02575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M. Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| |
Collapse
|
27
|
Kamitani M, Yujiri K, Yuge H. Hemisphere and Distance-Dependent Steric Analysis of PNN Iron Pincer Complexes Using SambVca 2.1 and Its Influence on Alkene Hydrosilylation. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masahiro Kamitani
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0373, Japan
| | - Kouta Yujiri
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0373, Japan
| | - Hidetaka Yuge
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0373, Japan
| |
Collapse
|