1
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Li G, Norton JR. Ti(III)-Catalyzed Anti-Markovnikov Reduction of Epoxides with Borohydride. Org Lett 2024; 26:1382-1386. [PMID: 38350153 DOI: 10.1021/acs.orglett.3c04304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
We have developed a Ti catalyst that carries out the anti-Markovnikov reduction of a wide range of epoxides; [BH4]- is used as both the electron and the hydrogen atom source. It requires only mild conditions and accommodates a broad range of epoxide substrates. The Ti catalyst is readily available and is environmentally friendly.
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Affiliation(s)
- Guangchen Li
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Jack R Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
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2
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Schmidt J, Domenianni LI, Leuschner M, Gansäuer A, Vöhringer P. Observing the Entry Events of a Titanium-Based Photoredox Catalytic Cycle in Real Time. Angew Chem Int Ed Engl 2023; 62:e202307178. [PMID: 37335756 DOI: 10.1002/anie.202307178] [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: 05/22/2023] [Revised: 06/19/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
Titanium-based catalysis in single electron transfer (SET) steps has evolved into a versatile approach for the synthesis of fine chemicals and first attempts have recently been made to enhance its sustainability by merging it with photo-redox (PR) catalysis. Here, we explore the photochemical principles of all-Ti-based SET-PR-catalysis, i.e. in the absence of a precious metal PR-co-catalyst. By combining time-resolved emission with ultraviolet-pump/mid-infrared-probe (UV/MIR) spectroscopy on femtosecond-to-microsecond time scales we quantify the dynamics of the critical events of entry into the catalytic cycle; namely, the singlet-triplet interconversion of the do-it-all titanocene(IV) PR-catalyst and its one-electron reduction by a sacrificial amine electron donor. The results highlight the importance of the PR-catalyst's singlet-triplet gap as a design guide for future improvements.
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Affiliation(s)
- Jonas Schmidt
- Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Luis I Domenianni
- Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Marcel Leuschner
- Kekulé Institute for Organic Chemistry and Biochemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé Institute for Organic Chemistry and Biochemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Peter Vöhringer
- Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Wegelerstraße 12, 53115, Bonn, Germany
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3
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Suzuki T, Ikeda W, Kanno A, Ikeuchi K, Tanino K. Diastereoselective Synthesis of trans-anti-Hydrophenanthrenes via Ti-mediated Radical Cyclization and Total Synthesis of Kamebanin. Chemistry 2023; 29:e202203511. [PMID: 36529687 DOI: 10.1002/chem.202203511] [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: 11/11/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/23/2022]
Abstract
Ent-kaurenes consist of an ABC-ring based on a trans-anti-hydrophenanthrene skeleton and a D ring with an exomethylene. Highly oxygen-functionalized ent-kauren-15-ones have promising antiinflammatory pharmacological activity. In this study, we developed a novel diastereoselective synthesis of trans-anti-hydrophenanthrenes via a Ti-mediated reductive radical cyclization. We also demonstrated the applicability of this method by developing the first total synthesis of (±)-kamebanin (longest linear sequence; 17 steps, overall yield; 6.5 %). Furthermore, this synthesis provided a formal semi-pinacol rearrangement for the construction of the quaternary carbon at C8 and a novel Thorpe-Ziegler-type reaction for the construction of the D-ring.
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Affiliation(s)
- Takahiro Suzuki
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Wataru Ikeda
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Ayaka Kanno
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Kazutada Ikeuchi
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
| | - Keiji Tanino
- Department of Chemistry, Faculty of Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan
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4
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Calvo-Molina A, del Horno E, Jover J, Pérez-Redondo A, Yélamos C, Zapata R. Monocyclopentadienyltitanium(III) Complexes with Hydridoborato Ligands. Organometallics 2023. [DOI: 10.1021/acs.organomet.2c00580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- Adrián Calvo-Molina
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
| | - Estefanía del Horno
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
| | - Jesús Jover
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Institut de Química Teòrica i Computacional (IQTC-UB), Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Adrián Pérez-Redondo
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
| | - Carlos Yélamos
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
| | - Rosa Zapata
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
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5
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Rosales Martínez A, Rodríguez-Maecker RN, Rodríguez-García I. Unifying the Synthesis of a Whole Family of Marine Meroterpenoids through a Biosynthetically Inspired Sequence of 1,2-Hydride and Methyl Shifts as Key Step. Mar Drugs 2023; 21:md21020118. [PMID: 36827159 PMCID: PMC9962294 DOI: 10.3390/md21020118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/15/2023] Open
Abstract
Marine meroterpenoids have attracted a great deal of attention from synthetic research groups due to their attractive and varied biological activities and their unique and diverse structures. In most cases, however, further biological studies have been severely limited mainly to the scarcity of natural supply and because almost none of the reported syntheses methods has enabled unified access for a large number of marine meroterpenoids with aureane and avarane skeletons. Based on our previous publications and the study of recent manuscripts on marine meroterpenoids, we have conceived a unified strategy for these fascinating marine compounds with aureane or avarane skeletons using available drimane compounds as starting materials. The key step is a biosynthetic sequence of 1,2-hydride and methyl shifts. This strategy is of great synthetic value to access marine meroterpenoids through easy chemical synthetic procedures. Finally, several retrosynthetic proposals are made for the future synthesis of several members of this class of meroterpenoids, focused on consolidating these 1,2-rearrangements as a versatile and unified strategy that could be widely used in the preparation of these marine meroterpenoids.
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Affiliation(s)
- Antonio Rosales Martínez
- Department of Chemical Engineering, Escuela Politécnica Superior, University of Sevilla, 41011 Sevilla, Spain
- Correspondence:
| | - Román Nicolay Rodríguez-Maecker
- Department of Energy and Mechanics, Carrera de Ingeniería Petroquímica, Universidad de las Fuerzas Armadas-ESPE, Latacunga 050150, Ecuador
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6
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Streuff J. Reductive Umpolung and Defunctionalization Reactions through Higher-Order Titanium(III) Catalysis. Synlett 2022. [DOI: 10.1055/s-0042-1751391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AbstractThe single-electron transfer from an in situ formed titanium(III) catalyst to ketones, imines, nitriles, Michael acceptors, and many other functions has enabled a large number of intra- and intermolecular reductive umpolung reactions. Likewise, it allows the homolytic cleavage of functional groups for selective defunctionalizations. These reactions often take place with the participation of two titanium(III) species, avoiding free-radical pathways and enabling high catalyst control of the reaction selectivity. This account discusses the development of the individual reactions together with the fundamental mechanistic discoveries that led to a better understanding of such titanium(III)-catalyzed processes in general.1 Introduction2 Active Titanium(III) Species and Additives3 Ketone-Nitrile Couplings4 Further Reductive Umpolung Reactions5 Catalytic Homolytic C–CN and C–SO2R Cleavage6 Conclusion
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7
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Aida K, Hirao M, Funabashi A, Sugimura N, Ota E, Yamaguchi J. Catalytic reductive ring opening of epoxides enabled by zirconocene and photoredox catalysis. Chem 2022. [DOI: 10.1016/j.chempr.2022.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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8
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Xie H, Wang S, Wang Y, Guo P, Shu XZ. Ti-Catalyzed Reductive Dehydroxylative Vinylation of Tertiary Alcohols. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05530] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Hao Xie
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
| | - Sheng Wang
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
| | - Yuquan Wang
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
| | - Peng Guo
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
| | - Xing-Zhong Shu
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
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9
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Del Horno E, Jover J, Mena M, Pérez-Redondo A, Yélamos C. Low-Valent Titanium Species Stabilized with Aluminum/Boron Hydride Fragments. Chemistry 2021; 28:e202103085. [PMID: 34735025 DOI: 10.1002/chem.202103085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Indexed: 11/09/2022]
Abstract
Low-valent titanium species were prepared by reaction of [TiCp*X3 ] (Cp*=η5 -C5 Me5 ; X=Cl, Br, Me) with LiEH4 (E=Al, B) or BH3 (thf), and their structures elucidated by experimental and theoretical methods. The treatment of trihalides [TiCp*X3 ] with LiAlH4 in ethereal solvents (L) leads to the hydride-bridged heterometallic complexes [{TiCp*(μ-H)}2 {(μ-H)2 AlX(L)}2 ] (L=thf, X=Cl, Br; L=OEt2 , X=Cl). Density functional theory (DFT) calculations for those compounds reveal an open-shell singlet ground state with a Ti-Ti bond and can be described as titanium(II) species. The theoretical analyses also show strong interactions between the Ti-Ti bond and the empty s orbitals of the Al atom of the AlH2 XL fragments, which behave as σ-accepting (Z-type) ligands. Analogous reactions of [TiCp*X3 ] with LiBH4 (2 and 3 equiv.) in tetrahydrofuran at room temperature and at 85 °C lead to the titanium(III) compounds [{TiCp*(BH4 )(μ-X)}2 ] (X=Cl, Br) and [{TiCp*(BH4 )(μ-BH4 )}2 ], respectively. The treatment of [TiCp*Me3 ] with 4 and 5 equiv. of BH3 (thf) produces the diamagnetic [{TiCp*(BH3 Me)}2 (μ-B2 H6 )] and paramagnetic [{TiCp*(μ-B2 H6 )}2 ] complexes, respectively.
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Affiliation(s)
- Estefanía Del Horno
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Jesús Jover
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Institut de Química Teòrica i Computacional (IQTC-UB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain
| | - Miguel Mena
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Adrián Pérez-Redondo
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
| | - Carlos Yélamos
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá, 28805 Alcalá de, Henares-Madrid, Spain
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10
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Abstract
Titanium is an attractive metal for catalytic reaction development: it is earth-abundant, inexpensive, and generally nontoxic. However-like most early transition metals-catalytic redox reactions with Ti are difficult because of the stability of the high-valent TiIV state. Understanding the fundamental mechanisms behind Ti redox processes is key for making progress toward potential catalytic applications. This Account details recent progress in Ti-catalyzed (and -mediated) oxidative amination reactions that proceed through formally TiII/TiIV catalytic cycles.This class of reactions is built on our initial discovery of Ti-catalyzed [2 + 2 + 1] pyrrole synthesis from alkynes and azobenzene, where detailed mechanistic studies have revealed important factors that allow for catalytic turnover despite the inherent difficulty of Ti redox. Two important conclusions from mechanistic studies are that (1) low-valent Ti intermediates in catalysis can be stabilized through coordination of π-acceptor substrates or products, where they can act as "redox-noninnocent" ligands through metal-to-ligand π back-donation, and (2) reductive elimination processes with Ti proceed through π-type electrocyclic (or pericyclic) reaction mechanisms rather than direct σ-bond coupling.The key reactive species in Ti-catalyzed oxidative amination reactions are Ti imidos (Ti≡NR), which can be generated from either aryl diazenes (RN═NR) or organic azides (RN3). These Ti imidos can then undergo [2 + 2] cycloadditions with alkynes, resulting in intermediates that can be coupled to an array of other unsaturated functional groups, including alkynes, alkenes, nitriles, and nitrosos. This basic reactivity pattern has been extended into a broad range of catalytic and stoichiometric oxidative multicomponent coupling reactions of alkynes and other reactive small molecules, leading to multicomponent syntheses of various heterocycles and aminated building blocks.For example, catalytic oxidative coupling of Ti imidos with two different alkynes leads to pyrroles, while stoichiometric oxidative coupling with alkynes and nitriles leads to pyrazoles. These heterocycle syntheses often yield substitution patterns that are complementary to those of classical condensation routes and provide access to new electron-rich, highly substituted heteroaromatic scaffolds. Furthermore, catalytic oxidative alkyne carboamination reactions can be accomplished via reaction of Ti imidos with alkynes and alkenes, yielding α,β-unsaturated imine or cyclopropylimine building blocks. New catalytic and stoichiometric oxidative amination methods such as alkyne α-diimination, isocyanide imination, and ring-opening oxidative amination of strained alkenes are continuously emerging as a result of better mechanistic understanding of Ti redox catalysis.Ultimately, these Ti-catalyzed and -mediated oxidative amination methods demonstrate the importance of examining often-overlooked elements like the early transition metals through the lens of modern catalysis: rather than a lack of utility, these elements frequently have undiscovered potential for new transformations with orthogonal or complementary selectivity to their late transition metal counterparts.
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Affiliation(s)
- Ian A. Tonks
- Department of Chemistry, University of Minnesota—Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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11
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Sumiyama K, Toriumi N, Iwasawa N. Use of Isopropyl Alcohol as a Reductant for Catalytic Dehydoxylative Dimerization of Benzylic Alcohols Utilizing Ti−O Bond Photohomolysis. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Keiichi Sumiyama
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
| | - Naoyuki Toriumi
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
| | - Nobuharu Iwasawa
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
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12
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Calogero F, Gualandi A, Matteo MD, Potenti S, Fermi A, Bergamini G, Cozzi PG. Photoredox Propargylation of Aldehydes Catalytic in Titanium. J Org Chem 2021; 86:7002-7009. [PMID: 33884879 PMCID: PMC8279488 DOI: 10.1021/acs.joc.1c00521] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
A practical and effective
photoredox propargylation of aldehydes
promoted by 10 mol % of [Cp2TiCl2] is presented.
No stoichiometric metals or scavengers are used for the process. A
catalytic amount of the cheap and simply prepared organic dye 3DPAFIPN
is used as the reductant for titanium. The reaction displayed a broad
scope, and no traces of allenyl isomers were detected for simple propargyl
bromide, whereas mixtures of propargyl and allenyl isomers were observed
for substituted propargyl bromides.
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Affiliation(s)
- Francesco Calogero
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
| | - Andrea Gualandi
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
| | - Marco Di Matteo
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
| | - Simone Potenti
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy.,Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Andrea Fermi
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
| | - Giacomo Bergamini
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
| | - Pier Giorgio Cozzi
- Alma Mater Studiorum, Università di Bologna, Dipartimento di Chimica "G. Ciamician", Via Selmi 2, 40126 Bologna, Italy
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13
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Hu P, Peters BK, Malapit CA, Vantourout JC, Wang P, Li J, Mele L, Echeverria PG, Minteer SD, Baran PS. Electroreductive Olefin-Ketone Coupling. J Am Chem Soc 2020; 142:20979-20986. [PMID: 33259715 DOI: 10.1021/jacs.0c11214] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A user-friendly approach is presented to sidestep the venerable Grignard addition to unactivated ketones to access tertiary alcohols by reversing the polarity of the disconnection. In this work a ketone instead acts as a nucleophile when adding to simple unactivated olefins to accomplish the same overall transformation. The scope of this coupling is broad as enabled using an electrochemical approach, and the reaction is scalable, chemoselective, and requires no precaution to exclude air or water. Multiple applications demonstrate the simplifying nature of the reaction on multistep synthesis, and mechanistic studies point to an intuitive mechanism reminiscent of other chemical reductants such as SmI2 (which cannot accomplish the same reaction).
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Affiliation(s)
- Pengfei Hu
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla 92037, California, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
| | - Byron K Peters
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla 92037, California, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
| | - Christian A Malapit
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City 84112, Utah, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
| | - Julien C Vantourout
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla 92037, California, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
| | - Pan Wang
- Center for Excellence of Process Science, Asymchem Laboratories (Tianjin) Co., Ltd. TEDA, Tianjin 300457, P. R. China
| | - Jinjun Li
- Center for Excellence of Process Science, Asymchem Laboratories (Tianjin) Co., Ltd. TEDA, Tianjin 300457, P. R. China
| | - Lucas Mele
- Minakem Recherche, 145 Chemin des Lilas, Beuvry-la-Forêt 59310, France
| | | | - Shelley D Minteer
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City 84112, Utah, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
| | - Phil S Baran
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla 92037, California, United States.,NSF Center for Synthetic Organic Electrochemistry, University of Utah, 315 South 1400 East, Salt Lake City 84112, Utah, United States
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14
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Martínez AR, Morales LP, Ojeda ED, Rodríguez MC, Rodríguez-García I. The Proven Versatility of Cp 2TiCl. J Org Chem 2020; 86:1311-1329. [PMID: 33147037 DOI: 10.1021/acs.joc.0c01233] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the last two decades, titanocene monochloride has been postulated as a monoelectronic transfer reagent capable of catalyzing an important variety of chemical transformations. In this Perspective, our contributions to this growing field of research are summarized and analyzed. Especially known have been our contributions in C-C bond formation reactions, hydrogen-atom transfer from water to radicals, and isomerization reactions, as well as the development of a catalytic cycle that has subsequently allowed the preparation of a great variety of natural terpenes. It is also worth mentioning our contribution in the postulation of this single-electron transfer agent (SET) as a new green catalyst with a broad range of applications in organic and organometallic chemistry. The most significant catalytic processes developed by other research groups are also briefly described, with special emphasis on the reaction mechanisms involved. Finally, a reflection is made on the future trends in the research of this SET, aimed at consolidating this chemical as a new green reagent that will be widely used in fine chemistry, green chemistry, and industrial chemical processes.
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Affiliation(s)
- Antonio Rosales Martínez
- Department of Chemical Engineering, Escuela Politécnica Superior, University of Sevilla, 41011 Sevilla, Spain
| | - Laura Pozo Morales
- Department of Chemical Engineering, Escuela Politécnica Superior, University of Sevilla, 41011 Sevilla, Spain
| | - Emilio Díaz Ojeda
- Department of Chemical Engineering, Escuela Politécnica Superior, University of Sevilla, 41011 Sevilla, Spain
| | - María Castro Rodríguez
- Department of Chemical Engineering, Escuela Politécnica Superior, University of Sevilla, 41011 Sevilla, Spain
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15
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Xie H, Guo J, Wang YQ, Wang K, Guo P, Su PF, Wang X, Shu XZ. Radical Dehydroxylative Alkylation of Tertiary Alcohols by Ti Catalysis. J Am Chem Soc 2020; 142:16787-16794. [DOI: 10.1021/jacs.0c07492] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hao Xie
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Jiandong Guo
- Hoffmann Institute of Advanced Materials, Postdoctoral Innovation Practice Base, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen 518055, China
| | - Yu-Quan Wang
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Ke Wang
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Peng Guo
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Pei-Feng Su
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Xiaotai Wang
- Hoffmann Institute of Advanced Materials, Postdoctoral Innovation Practice Base, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen 518055, China
- Department of Chemistry, University of Colorado Denver, Campus Box 194, P.O. Box 173364, Denver, Colorado 80217-3364, United States
| | - Xing-Zhong Shu
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
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16
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Fermi A, Gualandi A, Bergamini G, Cozzi PG. Shining Light on Ti
IV
Complexes: Exceptional Tools for Metallaphotoredox Catalysis. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000966] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Andrea Fermi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
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17
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Affiliation(s)
- Yuqing Chen
- Zhang Dayu School of Chemistry State Key Laboratory of Fine ChemicalsDalian University of Technology Dalian 116024 China
| | - Shuangjie Lin
- Zhang Dayu School of Chemistry State Key Laboratory of Fine ChemicalsDalian University of Technology Dalian 116024 China
| | - Fusheng Li
- Zhang Dayu School of Chemistry State Key Laboratory of Fine ChemicalsDalian University of Technology Dalian 116024 China
| | - Xinhai Zhang
- School of Traffic and Materials EngineeringHebi Polytechnic Hebi 458030 China
| | - Luqing Lin
- Zhang Dayu School of Chemistry State Key Laboratory of Fine ChemicalsDalian University of Technology Dalian 116024 China
| | - Lei Shi
- Zhang Dayu School of Chemistry State Key Laboratory of Fine ChemicalsDalian University of Technology Dalian 116024 China
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18
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Zhang Z, Hilche T, Slak D, Rietdijk NR, Oloyede UN, Flowers RA, Gansäuer A. Titanocenes as Photoredox Catalysts Using Green-Light Irradiation. Angew Chem Int Ed Engl 2020; 59:9355-9359. [PMID: 32216162 PMCID: PMC7317808 DOI: 10.1002/anie.202001508] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/08/2020] [Indexed: 11/16/2022]
Abstract
Irradiation of Cp2 TiCl2 with green light leads to electronically excited [Cp2 TiCl2 ]*. This complex constitutes an efficient photoredox catalyst for the reduction of epoxides and for 5-exo cyclizations of suitably unsaturated epoxides. To the best of our knowledge, our system is the first example of a molecular titanium photoredox catalyst.
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Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Daniel Slak
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Niels R. Rietdijk
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | | | | | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
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19
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Zhang Z, Hilche T, Slak D, Rietdijk NR, Oloyede UN, Flowers RA, Gansäuer A. Titanocenes as Photoredox Catalysts Using Green‐Light Irradiation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001508] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Daniel Slak
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Niels R. Rietdijk
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | | | | | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
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20
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Horno ED, Jiménez-Aparicio R, Mena M, Pérez-Redondo A, Priego JL, Yélamos C. Preparation of Dimeric Monopentamethylcyclopentadienyltitanium(III) Dihalides and Related Derivatives. Inorg Chem 2020; 59:3740-3752. [PMID: 32101433 DOI: 10.1021/acs.inorgchem.9b03399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis, crystal structure, and reactivity of a series of half-sandwich titanium(III) dihalide complexes [Ti(η5-C5Me5)X2] (X = Cl, Br, I) and several of its Lewis base derivatives were investigated. The reaction of the trihalides [Ti(η5-C5Me5)X3] (X = Cl (1), Br (2), I (3)) with LiAlH4 (≥1 equiv) in toluene at room temperature results in the formation of the halide-bridged dimers [{Ti(η5-C5Me5)X(μ-X)}2] (X = Cl (4), Br (5), I (6)). The treatment of 4 with [Li{N(SiMe3)2}] (≥2 equiv) at room temperature affords the precipitation of the amido titanium(III) complex [{Ti(η5-C5Me5)(μ-Cl){N(SiMe3)2}}2] (7), but analogous reactions of 4 with other lithium reagents [LiR] (R = Me, CH2SiMe3, NMe2) lead to disproportionation into titanium(IV) [Ti(η5-C5Me5)R3] and presumably titanium(II) derivatives. Similarly, complex 4 in solution at temperatures higher than 100 °C undergoes disproportionation as demonstrated by its reactions with cobaltocene and N-(4-methylbenzylidene)aniline yielding the ionic paramagnetic compound [Co(η5-C5H5)2][Ti(η5-C5Me5)Cl3] (8) and the diamagnetic diazatitanacyclopentane [Ti(η5-C5Me5)Cl{N(Ph)CH(p-tolyl)}2], respectively. Treatment of complex 4 with 2 equiv of 2,6-dimethylphenylisocyanide or tert-butylisocyanide in toluene at room temperature affords the paramagnetic titanium(III) dinuclear adducts [{Ti(η5-C5Me5)Cl(μ-Cl)(CNR)}2] (R = 2,6-Me2C6H3 (9), tBu (10)). Magnetic studies for polycrystalline 9 show that it displays a weak intramolecular antiferromagnetic coupling between the Ti ions, which is consistent with the long Ti-Ti distance of 3.857(1) Å determined by X-ray diffraction. The isocyanide ligands in complex 10 undergo a reductive coupling reaction in toluene to give the titanium(IV) iminoacyl derivative [{Ti(η5-C5Me5)Cl2}2(μ-η2:η2-tBuN═C-C═NtBu)] (11). Whereas an analogous dinuclear structure was found in the aqua titanium(III) complex [{Ti(η5-C5Me5)Cl(μ-Cl)(OH2)}2] (12), resulting from the reaction of 4 with adventitious amounts of water, compound 4 reacts with excess ammonia to give a mononuclear adduct [Ti(η5-C5Me5)Cl2(NH3)2] (13) with a robust layered pattern in the solid state.
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Affiliation(s)
| | - Reyes Jiménez-Aparicio
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | | | | | - José Luis Priego
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
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21
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Gualandi A, Calogero F, Mazzarini M, Guazzi S, Fermi A, Bergamini G, Cozzi PG. Cp2TiCl2-Catalyzed Photoredox Allylation of Aldehydes with Visible Light. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00348] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Andrea Gualandi
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Francesco Calogero
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Martino Mazzarini
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Simone Guazzi
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Andrea Fermi
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica “Giacomo Ciamician”, Alma Mater Studiorum − Università di Bologna, Via Selmi 2, Bologna 40126, Italy
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22
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Torres‐García I, López‐Martínez JL, Martínez‐Martínez R, Oltra JE, Muñoz‐Dorado M, Rodríguez‐García I, Álvarez‐Corral M. The half‐sandwich titanocene CpTi
III
Cl
2
as efficient system for the preparation of 2,5‐dihydrofurans
via
α‐allenols. Appl Organomet Chem 2020. [DOI: 10.1002/aoc.5244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | | | | | - J. Enrique Oltra
- Dpto. Química Orgánica, Facultad de CienciasUniversidad de Granada Granada E18071 Spain
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23
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Manßen M, Schafer LL. Titanium catalysis for the synthesis of fine chemicals – development and trends. Chem Soc Rev 2020; 49:6947-6994. [DOI: 10.1039/d0cs00229a] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Atlas as a Titan(ium) is holding the earth-abundant chemistry world. Titanium is the second most abundant transition metal, is a key player in important industrial processes (e.g. polyethylene) and shows much promise for diverse applications in the future.
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Affiliation(s)
- Manfred Manßen
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| | - Laurel L. Schafer
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
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24
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González-Delgado JA, Arteaga JF. Control of Homocoupling Versus Reduction in Titanium(III)-Mediated Radical Opening of Styrene Oxides. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- José A. González-Delgado
- CIQSO-Center for Research in Sustainable Chemistry and Department of Chemistry; University of Huelva; Campus de El Carmen s/n E-21071 Huelva Spain
| | - Jesús F. Arteaga
- CIQSO-Center for Research in Sustainable Chemistry and Department of Chemistry; University of Huelva; Campus de El Carmen s/n E-21071 Huelva Spain
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25
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Chen Y. Advances in the Synthesis of Methylated Products through Indirect Approaches. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201901240] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yantao Chen
- Medicinal Chemistry, Research and Early DevelopmentCardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca 43183 Gothenburg Sweden
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26
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Abstract
New catalytic strategies that leverage single-electron redox events have provided chemists with useful tools for solving synthetic problems. In this context, Ti offers opportunities that are complementary to late transition metals for reaction discovery. Following foundational work on epoxide reductive functionalization, recent methodological advances have significantly expanded the repertoire of Ti radical chemistry. This Synopsis summarizes recent developments in the burgeoning area of Ti radical catalysis with a focus on innovative catalytic strategies such as radical redox-relay and dual catalysis.
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Affiliation(s)
- Terry McCallum
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Xiangyu Wu
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Song Lin
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
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27
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Mühlhaus F, Weißbarth H, Dahmen T, Schnakenburg G, Gansäuer A. Merging Regiodivergent Catalysis with Atom-Economical Radical Arylation. Angew Chem Int Ed Engl 2019; 58:14208-14212. [PMID: 31394024 PMCID: PMC6852184 DOI: 10.1002/anie.201908860] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 12/11/2022]
Abstract
A titanocene-catalyzed regiodivergent radical arylation is described that allows access to either enantiomerically pure tetrahydroquinolines or indolines from a common starting material. The regioselectivity of epoxide opening that results in the high selectivity of heterocycle formation is controlled by two factors, the absolute configuration of the enantiopure ligands of the (C5 H4 R)2 TiX2 catalyst and the inorganic ligand X (X=Cl, OTs). The overall reaction is atom-economical and constitutes a radical Friedel-Crafts alkylation.
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Affiliation(s)
- Felix Mühlhaus
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Hendrik Weißbarth
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Tobias Dahmen
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Gregor Schnakenburg
- Institut für Anorganische ChemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
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28
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Mühlhaus F, Weißbarth H, Dahmen T, Schnakenburg G, Gansäuer A. Merging Regiodivergent Catalysis with Atom‐Economical Radical Arylation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908860] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Felix Mühlhaus
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Hendrik Weißbarth
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Tobias Dahmen
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Gregor Schnakenburg
- Institut für Anorganische Chemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
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29
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Rosales Martínez A, Pozo Morales L, Díaz Ojeda E. Cp2TiCl-catalyzed, concise synthetic approach to marine natural product (±)-cyclozonarone. SYNTHETIC COMMUN 2019. [DOI: 10.1080/00397911.2019.1633671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
| | - Laura Pozo Morales
- Department of Chemical Engineering, University of Sevilla, Sevilla, Spain
| | - Emilio Díaz Ojeda
- Department of Chemical Engineering, University of Sevilla, Sevilla, Spain
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30
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Liedtke T, Hilche T, Klare S, Gansäuer A. Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry: Additives and Solvents. CHEMSUSCHEM 2019; 12:3166-3171. [PMID: 30779429 DOI: 10.1002/cssc.201900344] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Cyclic voltammetry-based screening method for Cp2 TiX-catalyzed reactions is extended to the screening of solvents other than tetrahydrofuran for bulk electrolysis of the catalyst and radical arylation. It was found that CH3 CN can be used as a solvent for both processes without additives. Furthermore, in tetrahydrofuran, squaramide L2 is more efficient than the previously reported supramolecular halide binder, Schreiner's thiourea L1. The results extend the usefulness of the proposed time and resource-efficient screening method for designing catalysis reactions in single-electron steps.
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Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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31
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Coward DL, Lake BRM, Poli R, Shaver MP. Radically Initiated Group Transfer Polymerization of Methacrylates by Titanium Amino-Phenolate Complexes. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Daniel L. Coward
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, U.K
| | - Benjamin R. M. Lake
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, U.K
| | - Rinaldo Poli
- CNRS, LCC (Laboratoire de Chimie de Coordination) and Université de Toulouse, UPS, INPT, 205 route de Narbonne, BP 44099, 31077 Toulouse Cedex 4, France
| | - Michael P. Shaver
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, U.K
- School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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32
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García-Castro M, García-Iriepa C, Del Horno E, Martín A, Mena M, Pérez-Redondo A, Temprado M, Yélamos C. The Puzzling Monopentamethylcyclopentadienyltitanium(III) Dichloride Reagent: Structure and Properties. Inorg Chem 2019; 58:5314-5324. [PMID: 30943022 DOI: 10.1021/acs.inorgchem.9b00437] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Following the track of the useful titanocene [Ti(η5-C5H5)2Cl] reagent in organic synthesis, the related half-sandwich titanium(III) derivatives [Ti(η5-C5R5)Cl2] are receiving increasing attention in radical chemistry of many catalyzed transformations. However, the structure of the active titanium(III) species remains unknown in the literature. Herein, we describe the synthesis, crystal structure, and electronic structure of titanium(III) aggregates of composition [{Ti(η5-C5Me5)Cl2} n]. The thermolysis of [Ti(η5-C5Me5)Cl2Me] (1) in benzene or hexane at 180 °C results in the clean formation of [{Ti(η5-C5Me5)Cl(μ-Cl)}2] (2), methane, and ethene. The treatment of 1 with excess pinacolborane in hexane at 65 °C leads to a mixture of 2 and the paramagnetic trimer [{Ti(η5-C5Me5)(μ-Cl)2}3] (3). The X-ray crystal structures of compounds 2 and 3 show Ti-Ti distances of 3.267(1) and 3.219(12) Å, respectively. Computational studies (CASPT2//CASSCF and BS DFT methods) for dimer 2 reveal a singlet ground state and a relatively large singlet-triplet energy gap. Nuclear magnetic resonance spectroscopy of 2 in aromatic hydrocarbon solutions and DFT calculations for several [{Ti(η5-C5Me5)Cl2} n] aggregates are consistent with the existence of an equilibrium between the diamagnetic dimer [{Ti(η5-C5Me5)Cl(μ-Cl)}2] and a paramagnetic tetramer [{Ti(η5-C5Me5)(μ-Cl)2}4] in solution. In contrast, complex 2 readily dissolves in tetrahydrofuran to give a green-blue solution from which blue crystals of the mononuclear adduct [Ti(η5-C5Me5)Cl2(thf)] (4) were grown.
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Affiliation(s)
- María García-Castro
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Cristina García-Iriepa
- Departamento de Química Analítica, Química Física e Ingeniería Química , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Departamento de Química , Universidad de La Rioja, Centro de Investigación en Síntesis Química (CISQ) , 26006 Logroño , Spain
| | - Estefanía Del Horno
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Avelino Martín
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Miguel Mena
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Adrián Pérez-Redondo
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Manuel Temprado
- Departamento de Química Analítica, Química Física e Ingeniería Química , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
| | - Carlos Yélamos
- Departamento de Química Orgánica y Química Inorgánica , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain.,Instituto de Investigación Química "Andrés M. del Río" (IQAR) , Universidad de Alcalá , 28805 Alcalá de Henares- Madrid , Spain
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33
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Zhang Z, Richrath RB, Gansäuer A. Merging Catalysis in Single Electron Steps with Photoredox Catalysis—Efficient and Sustainable Radical Chemistry. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00787] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
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Cheng JT, Zheng X, Huang PQ. Construction of multifunctional heterocycles bearing aza-quaternary carbons by titanocene-catalyzed umpolung reactions. Tetrahedron 2019. [DOI: 10.1016/j.tet.2018.11.067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Leijendekker LH, Weweler J, Leuther TM, Kratzert D, Streuff J. Development, Scope, and Applications of Titanium(III)-Catalyzed Cyclizations to Aminated N-Heterocycles. Chemistry 2019; 25:3382-3390. [PMID: 30615817 DOI: 10.1002/chem.201805909] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Indexed: 01/30/2023]
Affiliation(s)
- Leonardus H. Leijendekker
- Institut für Organische Chemie; Albert-Ludwigs-Universität Freiburg; Albertstr. 21 79104 Freiburg im Breisgau Germany
| | - Jens Weweler
- Institut für Organische Chemie; Albert-Ludwigs-Universität Freiburg; Albertstr. 21 79104 Freiburg im Breisgau Germany
| | - Tobias M. Leuther
- Institut für Organische Chemie; Albert-Ludwigs-Universität Freiburg; Albertstr. 21 79104 Freiburg im Breisgau Germany
| | - Daniel Kratzert
- Institut für Anorganische und Analytische Chemie; Albert-Ludwigs-Universität Freiburg; Albertstr. 21 79104 Freiburg im Breisgau Germany
| | - Jan Streuff
- Institut für Organische Chemie; Albert-Ludwigs-Universität Freiburg; Albertstr. 21 79104 Freiburg im Breisgau Germany
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López-Martínez JL, Torres-García I, Rodríguez-García I, Muñoz-Dorado M, Álvarez-Corral M. Stereoselective Barbier-Type Allylations and Propargylations Mediated by CpTiCl 3. J Org Chem 2019; 84:806-816. [PMID: 30582330 DOI: 10.1021/acs.joc.8b02643] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
CpTiCl2, prepared in situ by manganese reduction of CpTiCl3, is an excellent new system for the Barbier-type allylation and propargylation of carbonyl compounds. It can be used in catalytic amounts when combined with Et3N·HBr/TMSBr, which acts as a regenerating system. The high regio- and stereoselectivity shown by this system makes it useful for prenylation and crotylation processes in the synthesis of natural products.
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Affiliation(s)
| | - Irene Torres-García
- Dpto. Química Orgánica , Universidad de Almería , ceiA3, 04120 Almería , Spain
| | | | - Manuel Muñoz-Dorado
- Dpto. Química Orgánica , Universidad de Almería , ceiA3, 04120 Almería , Spain
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Beaumier EP, Pearce AJ, See XY, Tonks IA. Modern applications of low-valent early transition metals in synthesis and catalysis. Nat Rev Chem 2019; 3:15-34. [PMID: 30989127 PMCID: PMC6462221 DOI: 10.1038/s41570-018-0059-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low-valent early transition metals are often intrinsically highly reactive as a result of their strong propensity toward oxidation to more stable high-valent states. Harnessing these highly reducing complexes for productive reactivity is potentially powerful for C-C bond construction, organic reductions, small-molecule activation and many other reactions that offer orthogonal chemoselectivity and/or regioselectivity patterns to processes promoted by late transition metals. Recent years have seen many exciting new applications of low-valent metals through building new catalytic and/or multicomponent reaction manifolds out of classical reactivity patterns. In this Review, we survey new methods that employ early transition metals and invoke low-valent precursors or intermediates in order to identify common themes and strategies in synthesis and catalysis.
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Affiliation(s)
- Evan P. Beaumier
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Adam J. Pearce
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Xin Yi See
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
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38
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Das S, Bhattacharjee J, Panda TK. Guanylation/cyclisation of amino acid esters using an imidazolin-2-iminato titanium initiator. Dalton Trans 2019; 48:7227-7235. [DOI: 10.1039/c8dt04630a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Catalytic hydroamination of amino acid esters with carbodiimides and isocyanates to furnish corresponding quinazolinone and urea derivatives using two TiIV complexes under mild conditions is reported.
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Affiliation(s)
- Suman Das
- Department of Chemistry
- Indian Institute of Technology Hyderabad
- Sangareddy 502285
- India
| | - Jayeeta Bhattacharjee
- Department of Chemistry
- Indian Institute of Technology Hyderabad
- Sangareddy 502285
- India
| | - Tarun K. Panda
- Department of Chemistry
- Indian Institute of Technology Hyderabad
- Sangareddy 502285
- India
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39
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Gordon J, Hildebrandt S, Dewese KR, Klare S, Gansäuer A, RajanBabu TV, Nugent WA. Demystifying Cp 2Ti(H)Cl and its Enigmatic Role in the Reactions of Epoxides with Cp 2TiCl. Organometallics 2018; 37:4801-4809. [PMID: 30733623 DOI: 10.1021/acs.organomet.8b00793] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of Cp2Ti(H)Cl in the reactions of Cp2TiCl with trisubstituted epoxides has been investigated in a combined experimental and computational study. Although Cp2Ti(H)Cl has generally been regarded as a robust species, its decomposition to Cp2TiCl and molecular hydrogen was found to be exothermic (ΔG = -11 kcal/mol when the effects of THF solvation are considered). In laboratory studies, Cp2Ti(H)Cl was generated using the reaction of 1,2-epoxy-1-methylcyclohexane with Cp2TiCl as a model. Rapid evolution of hydrogen gas was demonstrated, indicating that Cp2Ti(H)Cl is indeed a thermally unstable molecule, which undergoes intermolecular reductive elimination of hydrogen under the reaction conditions. The stoichiometry of the reaction (Cp2TiCl:epoxide = 1:1) and the quantity of hydrogen produced (1 mole per 2 moles of epoxide) is consistent with this assertion. The diminished yield of allylic alcohol from these reactions under the conditions of protic versus aprotic catalysis can be understood in terms of the predominant titanium(III) present in solution. Under the conditions of protic catalysis, Cp2TiCl complexes with collidine hydrochloride and the titanium(III) center is less available for "cross-disproportionation" with carbon-centered radicals; this leads to by-products from radical capture by hydrogen atom transfer, resulting in a saturated alcohol.
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Affiliation(s)
- Jonathan Gordon
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Sven Hildebrandt
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Kendra R Dewese
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - T V RajanBabu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - William A Nugent
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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Gandeepan P, Müller T, Zell D, Cera G, Warratz S, Ackermann L. 3d Transition Metals for C-H Activation. Chem Rev 2018; 119:2192-2452. [PMID: 30480438 DOI: 10.1021/acs.chemrev.8b00507] [Citation(s) in RCA: 1444] [Impact Index Per Article: 240.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
C-H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C-H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C-H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C-H activation until summer 2018.
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Affiliation(s)
- Parthasarathy Gandeepan
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
| | - Thomas Müller
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
| | - Daniel Zell
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
| | - Gianpiero Cera
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
| | - Svenja Warratz
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie , Georg-August-Universität Göttingen , Tammannstraße 2 , 37077 Göttingen , Germany
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41
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Benito Iglesias D, Herrero Teijón P, Rubio González R, Fernández-Mateos A. Synthesis of trans
-β-Elemene. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- D. Benito Iglesias
- Departmento de Química Orgánica; Universidad de Salamanca; Plaza de los Caídos s/n 37008 Salamanca Spain
| | - P. Herrero Teijón
- Departmento de Química Orgánica; Universidad de Salamanca; Plaza de los Caídos s/n 37008 Salamanca Spain
| | - Rosa Rubio González
- Departmento de Química Orgánica; Universidad de Salamanca; Plaza de los Caídos s/n 37008 Salamanca Spain
| | - A. Fernández-Mateos
- Departmento de Química Orgánica; Universidad de Salamanca; Plaza de los Caídos s/n 37008 Salamanca Spain
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42
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Davis-Gilbert ZW, Kawakita K, Blechschmidt DR, Tsurugi H, Mashima K, Tonks IA. In Situ Catalyst Generation and Benchtop-Compatible Entry Points for Ti II/Ti IV Redox Catalytic Reactions. Organometallics 2018; 37:4439-4445. [PMID: 31802785 PMCID: PMC6892472 DOI: 10.1021/acs.organomet.8b00474] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of several in situ generated catalyst systems for Ti-catalyzed oxidative nitrene transfer reactions is reported. The simplest and widely applicable catalyst system, TiCl4(THF)2/Zn0, can be set up on the benchtop under air. This system uses commercially available reagents and can be used as an entry point for TiII/TiIV multicomponent redox reactions for the synthesis of pyrroles, α,γ-unsaturated imines, α,β-unsaturated imines, cyclopropylimines, and arenes.
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Affiliation(s)
- Zachary W. Davis-Gilbert
- Department of Chemistry, University of Minnesota—Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Kento Kawakita
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Daniel R. Blechschmidt
- Department of Chemistry, University of Minnesota—Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota—Twin Cities, Minneapolis, Minnesota 55455, United States
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Abstract
Titanocene bis-arylthiolates [(C5H4X)(C5H4Y)Ti(SC6H4R)2] (X,Y = H, Cl; R = H, Me) can be prepared from the corresponding titanocene dichlorides by reacting with the thiols in the presence of DABCO as a base. They react with n-butyl lithium to give unstable Ti(III) radical anions. While the unsubstituted thiolates (X = Y = R = H) react with lithium Di-isopropylamide by decomposing to dimeric fulvalene-bridged and thiolate-bridged Ti(III) compounds, the ring-chlorinated compounds can be deprotonated with LDA and give appropriate electrophiles di-substituted and tri-substituted titanocene dithiolates.
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44
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Chenniappan VK, Silwal S, Rahaim RJ. Ni/Ti Dual Catalytic Cross-Coupling of Nitriles and Organobromides To Access Ketones. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00244] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vinoth Kumar Chenniappan
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences 1, Stillwater, Oklahoma 74078, United States
| | - Sajan Silwal
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences 1, Stillwater, Oklahoma 74078, United States
| | - Ronald J. Rahaim
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences 1, Stillwater, Oklahoma 74078, United States
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45
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Liedtke T, Spannring P, Riccardi L, Gansäuer A. Mechanism-Based Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800731] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Peter Spannring
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Ludovico Riccardi
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
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46
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Liedtke T, Spannring P, Riccardi L, Gansäuer A. Mechanism-Based Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry. Angew Chem Int Ed Engl 2018; 57:5006-5010. [PMID: 29488673 DOI: 10.1002/anie.201800731] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/22/2018] [Indexed: 12/16/2022]
Abstract
A cyclic-voltammetry-based screening method for Cp2 TiX-catalyzed reactions is introduced. Our mechanism-based approach enables the study of the influence of various additives on the electrochemically generated active catalyst Cp2 TiX, which is in equilibrium with catalytically inactive [Cp2 TiX2 ]- . Thioureas and ureas are most efficient in the generation of Cp2 TiX in THF. Knowing the precise position of the equilibrium between Cp2 TiX and [Cp2 TiX2 ]- allowed us to identify reaction conditions for the bulk electrolysis of Cp2 TiX2 complexes and for Cp2 TiX-catayzed radical arylations without having to carry out the reactions. Our time- and resource-efficient approach is of general interest for the design of catalytic reactions that proceed in single-electron steps.
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Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Peter Spannring
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Ludovico Riccardi
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
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47
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Richrath RB, Olyschläger T, Hildebrandt S, Enny DG, Fianu GD, Flowers RA, Gansäuer A. Cp 2 TiX Complexes for Sustainable Catalysis in Single-Electron Steps. Chemistry 2018; 24:6371-6379. [PMID: 29327511 DOI: 10.1002/chem.201705707] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 12/18/2022]
Abstract
We present a combined electrochemical, kinetic, and synthetic study with a novel and easily accessible class of titanocene catalysts for catalysis in single-electron steps. The tailoring of the electronic properties of our Cp2 TiX-catalysts that are prepared in situ from readily available Cp2 TiX2 is achieved by varying the anionic ligand X. Of the complexes investigated, Cp2 TiOMs proved to be either equal or substantially superior to the best catalysts developed earlier. The kinetic and thermodynamic properties pertinent to catalysis have been determined. They allow a mechanistic understanding of the subtle interplay of properties required for an efficient oxidative addition and reduction. Therefore, our study highlights that efficient catalysts do not require the elaborate covalent modification of the cyclopentadienyl ligands.
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Affiliation(s)
- Ruben B Richrath
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Theresa Olyschläger
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Sven Hildebrandt
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Daniel G Enny
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Godfred D Fianu
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
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48
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Yeung D, Penafiel J, Zijlstra HS, McIndoe JS. Oxidation of Titanocene(III): The Deceptive Simplicity of a Color Change. Inorg Chem 2017; 57:457-461. [DOI: 10.1021/acs.inorgchem.7b02705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Darien Yeung
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Johanne Penafiel
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Harmen S. Zijlstra
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - J. Scott McIndoe
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
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49
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Lee KN, Ngai MY. Recent developments in transition-metal photoredox-catalysed reactions of carbonyl derivatives. Chem Commun (Camb) 2017; 53:13093-13112. [PMID: 29125152 PMCID: PMC5930931 DOI: 10.1039/c7cc06287g] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Single-electron reduction of C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds of aldehydes, ketones, and imines results in the formation of ketyl and α-aminoalkyl anion radicals, respectively. These reactive intermediates are characterized by an altered electronic character with respect to their parent molecules and undergo a diverse range of synthetically useful transformations, which are not available to even-electron species. This Review summarizes the reactions of ketyl and α-aminyl radicals generated from carbonyl derivatives under transition-metal photoredox-catalysed conditions. We primarily focus on recent developments in the field, as well as give a brief overview of catalytic enantioselective transformations that provide a means to achieve precise stereocontrol over the reactivity of ion radicals.
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Affiliation(s)
- Katarzyna N Lee
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, USA.
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50
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Martínez AR, Rodríguez MC, Rodríguez-García I, Morales LP, Maecker RNR. Titanocene dichloride: A new green reagent in organic chemistry. CHINESE JOURNAL OF CATALYSIS 2017. [DOI: 10.1016/s1872-2067(17)62894-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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