1
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Lin Z, Ren H, Lin X, Yu X, Zheng J. Synthesis of Azabicyclo[3.1.1]heptenes Enabled by Catalyst-Controlled Annulations of Bicyclo[1.1.0]butanes with Vinyl Azides. J Am Chem Soc 2024; 146:18565-18575. [PMID: 38935924 DOI: 10.1021/jacs.4c04485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Bridged bicyclic scaffolds are emerging bioisosteres of planar aromatic rings under the concept of "escape from flatland". However, adopting this concept into the exploration of bioisosteres of pyridines remains elusive due to the challenge of incorporating a N atom into such bridged bicyclic structures. Herein, we report practical routes for the divergent synthesis of 2- and 3-azabicyclo[3.1.1]heptenes (aza-BCHepes) as potential bioisosteres of pyridines from the readily accessible vinyl azides and bicyclo[1.1.0]butanes (BCBs) via two distinct catalytic annulations. The reactivity of vinyl azides tailored with BCBs is the key to achieving divergent transformations. TiIII-catalyzed single-electron reductive generation of C-radicals from BCBs allows a concise (3 + 3) annulation with vinyl azides, affording novel 2-aza-BCHepe scaffolds. In contrast, scandium catalysis enables an efficient dipolar (3 + 2) annulation with vinyl azides to generate 2-azidobicyclo[2.1.1]hexanes, which subsequently undergo a chemoselective rearrangement to construct 3-aza-BCHepes. Both approaches efficiently deliver unique azabicyclo[3.1.1]heptene scaffolds with a high functional group tolerance. The synthetic utility has been further demonstrated by scale-up reactions and diverse postcatalytic transformations, providing valuable azabicyclics including 2- and 3-azabicyclo[3.1.1]heptanes and rigid bicyclic amino esters. In addition, the related sp2-hybridized nitrogen atom and the similar geometric property between pyridines and corresponding aza-BCHepes indicate that they are promising bioisosteres of pyridines.
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Affiliation(s)
- Zhongren Lin
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education; School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Haosong Ren
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education; School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Xinbo Lin
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education; School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Xinhong Yu
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education; School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Jun Zheng
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education; School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China
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2
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Liu Y, Wu Z, Shan JR, Yan H, Hao EJ, Shi L. Titanium catalyzed [2σ + 2π] cycloaddition of bicyclo[1.1.0]-butanes with 1,3-dienes for efficient synthesis of stilbene bioisosteres. Nat Commun 2024; 15:4374. [PMID: 38782978 PMCID: PMC11116475 DOI: 10.1038/s41467-024-48494-9] [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: 08/26/2023] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
Natural stilbenes have shown significant potential in the prevention and treatment of diseases due to their diverse pharmacological activities. Here we present a mild and effective Ti-catalyzed intermolecular radical-relay [2σ + 2π] cycloaddition of bicyclo[1.1.0]-butanes and 1,3-dienes. This transformation enables the synthesis of bicyclo[2.1.1]hexane (BCH) scaffolds containing aryl vinyl groups with excellent regio- and trans-selectivity and broad functional group tolerance, thus offering rapid access to structurally diverse stilbene bioisosteres.
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Affiliation(s)
- Yonghong Liu
- Cancer Hospital of Dalian University of Technology, 116024, Dalian, China
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China
| | - Zhixian Wu
- Cancer Hospital of Dalian University of Technology, 116024, Dalian, China
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China
| | - Jing-Ran Shan
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Huaipu Yan
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China
| | - Er-Jun Hao
- Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China.
| | - Lei Shi
- Cancer Hospital of Dalian University of Technology, 116024, Dalian, China.
- School of Chemistry, Dalian University of Technology, 116024, Dalian, China.
- Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China.
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3
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Lee WCC, Zhang XP. Metalloradical Catalysis: General Approach for Controlling Reactivity and Selectivity of Homolytic Radical Reactions. Angew Chem Int Ed Engl 2024; 63:e202320243. [PMID: 38472114 PMCID: PMC11097140 DOI: 10.1002/anie.202320243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/14/2024]
Abstract
Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic synthesis over the past two centuries has predominantly relied on the exploration and utilization of chemical reactions rooted in two-electron heterolytic ionic chemistry. While one-electron homolytic radical chemistry is both rich in fundamental reactivities and attractive with practical advantages, the synthetic application of radical reactions has been long hampered by the formidable challenges associated with the control over reactivity and selectivity of high-energy radical intermediates. To fully harness the untapped potential of radical chemistry for organic synthesis, there is a pressing need to formulate radically different concepts and broadly applicable strategies to address these outstanding issues. In pursuit of this objective, researchers have been actively developing metalloradical catalysis (MRC) as a comprehensive framework to guide the design of general approaches for controlling over reactivity and stereoselectivity of homolytic radical reactions. Essentially, MRC exploits the metal-centered radicals present in open-shell metal complexes as one-electron catalysts for homolytic activation of substrates to generate metal-entangled organic radicals as the key intermediates to govern the reaction pathway and stereochemical course of subsequent catalytic radical processes. Different from the conventional two-electron catalysis by transition metal complexes, MRC operates through one-electron chemistry utilizing stepwise radical mechanisms.
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Affiliation(s)
- Wan-Chen Cindy Lee
- Department of Chemistry, Boston College, Merkert Chemistry Center, Chestnut Hill, Massachusetts 02467 (USA)
| | - X. Peter Zhang
- Department of Chemistry, Boston College, Merkert Chemistry Center, Chestnut Hill, Massachusetts 02467 (USA)
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4
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Sun W, Zhao M, Meng Y, Zheng C, Yang K, Wang S, Ke C, Zhang Z. Photoinduced [3 + 2] Cycloadditions of Aryl Cyclopropyl Ketones with Alkynes and Alkenes. Org Lett 2024; 26:3762-3766. [PMID: 38678544 DOI: 10.1021/acs.orglett.4c00843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
The five-membered ring skeleton is one of the most pivotal in the area of pharmaceutical and natural products. [3 + 2] cycloadditions of cyclopropyl and unsaturated compounds are a highly efficient and atom-economical way to build a five-member compound. The previous works about the kind of [3 + 2] cycloadditions usually utilized metal or organic small molecule catalysts. However, an ideal [3 + 2] cycloaddition reaction that smoothly happens without any additives and catalysts under mild conditions is underdeveloped. Hence, we report [3 + 2] cycloadditions of aryl cyclopropyl without any additives and catalysts under purple LED. In this method, a broad scope of cyclopropyl, alkyne, and alkene was very compatible, especially drug derivatives ibuprofen and Ioxoprofen, to obtain the corresponding cycloaddition product with a good yield up to 93%.
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Affiliation(s)
- Wujuan Sun
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, P. R. China
| | - Mengyao Zhao
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, P. R. China
| | - Yihan Meng
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Chuqiao Zheng
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Kexin Yang
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Sichang Wang
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, P. R. China
| | - Congyu Ke
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, P. R. China
| | - Zongnan Zhang
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China
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5
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Mansell JI, Yu S, Li M, Pye E, Yin C, Beltran F, Rossi-Ashton JA, Romano C, Kaltsoyannis N, Procter DJ. Alkyl Cyclopropyl Ketones in Catalytic Formal [3 + 2] Cycloadditions: The Role of SmI 2 Catalyst Stabilization. J Am Chem Soc 2024; 146:12799-12807. [PMID: 38662638 PMCID: PMC11082888 DOI: 10.1021/jacs.4c03073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 05/09/2024]
Abstract
Alkyl cyclopropyl ketones are introduced as versatile substrates for catalytic formal [3 + 2] cycloadditions with alkenes and alkynes and previously unexplored enyne partners, efficiently delivering complex, sp3-rich products. The key to effectively engaging this relatively unreactive new substrate class is the use of SmI2 as a catalyst in combination with substoichiometric amounts of Sm0; the latter likely acting to prevent catalyst deactivation by returning SmIII to the catalytic cycle. In the absence of Sm0, background degradation of the SmI2 catalyst can outrun product formation. For the most recalcitrant alkyl cyclopropyl ketones, catalysis is "switched-on" using these new robust conditions, and otherwise unattainable products are delivered. Combined experimental and computational studies have been used to identify and probe reactivity trends among alkyl cyclopropyl ketones, including more complex bicyclic alkyl cyclopropyl ketones, which react quickly with various partners to give complex products. In addition to establishing alkyl cyclopropyl ketones as a new substrate class in a burgeoning field of catalysis, our study provides vital mechanistic insight and robust, practical approaches for the nascent field of catalysis with SmI2.
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Affiliation(s)
- Jack I. Mansell
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Song Yu
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Muze Li
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Emma Pye
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Chaofan Yin
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Frédéric Beltran
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - James A. Rossi-Ashton
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Ciro Romano
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Nikolas Kaltsoyannis
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - David J. Procter
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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6
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Tcyrulnikov S, Hubbell AK, Pedro D, Reyes GP, Monfette S, Weix DJ, Hansen EC. Computationally Guided Ligand Discovery from Compound Libraries and Discovery of a New Class of Ligands for Ni-Catalyzed Cross-Electrophile Coupling of Challenging Quinoline Halides. J Am Chem Soc 2024; 146:6947-6954. [PMID: 38427582 DOI: 10.1021/jacs.3c14607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Although screening technology has heavily impacted the fields of metal catalysis and drug discovery, its application to the discovery of new catalyst classes has been limited. The diversity of on- and off-cycle pathways, combined with incomplete mechanistic understanding, means that screens of potential new ligands have thus far been guided by intuitive analysis of the metal binding potential. This has resulted in the discovery of new classes of ligands, but the low hit rates have limited the use of this strategy because large screens require considerable cost and effort. Here, we demonstrate a method to identify promising screening directions via simple and scalable computational and linear regression tools that leads to a substantial improvement in hit rate, enabling the use of smaller screens to find new ligands. The application of this approach to a particular example of Ni-catalyzed cross-electrophile coupling of aryl halides with alkyl halides revealed a previously overlooked trend: reactions with more electron-poor amidine ligands result in a higher yield. Focused screens utilizing this trend were more successful than serendipity-based screening and led to the discovery of two new types of ligands, pyridyl oxadiazoles and pyridyl oximes. These ligands are especially effective for couplings of bromo- and chloroquinolines and isoquinolines, where they are now the state of the art. The simplicity of these models with parameters derived from metal-free ligand structures should make this approach scalable and widely accessible.
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Affiliation(s)
- Sergei Tcyrulnikov
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Aran K Hubbell
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Dylan Pedro
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Giselle P Reyes
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Sebastien Monfette
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Daniel J Weix
- University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Eric C Hansen
- Chemical Research and Development, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
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7
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Yu P, Zhang W, Lin S. Enantioselective radical cascade cyclization via Ti-catalyzed redox relay. Tetrahedron Lett 2023; 125:154617. [PMID: 37449084 PMCID: PMC10338015 DOI: 10.1016/j.tetlet.2023.154617] [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] [Indexed: 07/18/2023]
Abstract
Radical cascade cyclization reactions provide an efficient method for the construction of polycyclic architectures with multiple stereogenic centers. However, achieving enantioselectivity control of this type of reaction is a challenging task. Here, we report an enantioselective cyclization of polyfunctional aryl cyclopropyl ketone and alkyne units, wherein the stereochemical outcome is directed by a chiral Ti(salen) catalyst. This transformation was proposed to proceed via a radical cascade process involving the reductive ring-opening of the cyclopropyl ketone followed by two annulation events entailing cyclization of the ensuing alkyl radical onto the alkyne and subsequent addition of the incipient vinyl radical to the Ti(IV)-enolate.
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Affiliation(s)
- Peng Yu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Wen Zhang
- 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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8
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Harmata AS, Roldan BJ, Stephenson CRJ. Formal Cycloadditions Driven by the Homolytic Opening of Strained, Saturated Ring Systems. Angew Chem Int Ed Engl 2023; 62:e202213003. [PMID: 36239998 PMCID: PMC9852095 DOI: 10.1002/anie.202213003] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 12/05/2022]
Abstract
The field of strain-driven, radical formal cycloadditions is experiencing a surge in activity motivated by a renaissance in free radical chemistry and growing demand for sp3 -rich ring systems. The former has been driven in large part by the rise of photoredox catalysis, and the latter by adoption of the "Escape from Flatland" concept in medicinal chemistry. In the years since these broader trends emerged, dozens of formal cycloadditions, including catalytic, asymmetric variants, have been developed that operate via radical mechanisms. While cyclopropanes have been studied most extensively, a variety of strained ring systems are amenable to the design of analogous reactions. Many of these processes generate lucrative, functionally decorated sp3 -rich ring systems that are difficult to access by other means. Herein, we summarize recent efforts in this area and analyze the state of the field.
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Affiliation(s)
- Alexander S. Harmata
- Department of Chemistry, University of Michigan 930 N University Ave Ann Arbor MI, 48109-1055
| | - Bec. J. Roldan
- Department of Chemistry, University of Michigan 930 N University Ave Ann Arbor MI, 48109-1055
| | - Corey R. J. Stephenson
- Department of Chemistry, University of Michigan 930 N University Ave Ann Arbor MI, 48109-1055
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9
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Xu M, Wang Z, Sun Z, Ouyang Y, Ding Z, Yu T, Xu L, Li P. Diboron(4)-Catalyzed Remote [3+2] Cycloaddition of Cyclopropanes via Dearomative/Rearomative Radical Transmission through Pyridine. Angew Chem Int Ed Engl 2022; 61:e202214507. [PMID: 36344444 DOI: 10.1002/anie.202214507] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Indexed: 11/09/2022]
Abstract
Ring structures such as pyridine, cyclopentane or their combinations are important motifs in bioactive molecules. In contrast to previous cycloaddition reactions that necessitated a directly bonded initiating functional group, this work demonstrated a novel through-(hetero)arene radical transmission concept for selective activation of a remote bond. An efficient, metal-free and atom-economical [3+2] cycloaddition between 4-pyridinyl cyclopropanes and alkenes or alkynes has been developed for modular synthesis of pyridine-substituted cyclopentanes, cyclopentenes and bicyclo[2.1.1]hexanes that are difficult to access using known methods. This complexity-building reaction was catalyzed by a very simple and inexpensive diboron(4) compound and took place via dearomative/rearomative processes. The substrate scope was broad and more than 100 new compounds were prepared in generally high yields. Mechanistic experiments and density function theory (DFT) investigation supported a radical relay catalytic cycle involving alkylidene dihydropyridine radical intermediates and boronyl radical transfer.
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Affiliation(s)
- Ming Xu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China
| | - Zhijun Wang
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi, Xinjiang, 832003, China
| | - Zhaohui Sun
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China
| | - Yizhao Ouyang
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China
| | - Zhengwei Ding
- Department of Medicinal Chemistry, School of Pharmacy, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Tao Yu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China
| | - Liang Xu
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi, Xinjiang, 832003, China
| | - Pengfei Li
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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10
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Yu C, He JH, Lu JM. Ion-in-Conjugation: A Promising Concept for Multifunctional Organic Semiconductors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2204023. [PMID: 36285771 DOI: 10.1002/smll.202204023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/11/2022] [Indexed: 06/16/2023]
Abstract
Most organic semiconductors (OSCs) consist of conjugated skeletons with flexible peripheral chains. Their weak intermolecular interactions from dispersion and induction forces result in environmental susceptibilities and are unsuitable for many multifunctional applications where direct exposure to external environments is unavoidable, such as gas absorption, chemical sensing, and catalysis. To exploit the advantages of inorganic semiconductors in OSCs, ion-in-conjugation (IIC) materials are proposed. An IIC material refers to any conjugated material (molecules, polymers, and crystals) in Kekule's structural formula containing stoichiometric ionic states in its conjugated backbone in the electronic ground state. In this review, the definitions, structures, synthesis, properties, and applications of IIC materials are described briefly. Four types of IIC material, including zwitterionic conjugated molecules/polymers, conjugated ionic dyes, π-d conjugated molecules and polymers, and coordinatively doped polymers, are reported. Their applications in gas sensing, humidity sensing, resistive memory devices, and thermal/photo-/electro-catalysis are demonstrated. The challenges and opportunities for future research are also discussed. It is expected that this work will inspire the design of new organic electronic information materials.
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Affiliation(s)
- Chuang Yu
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Jing-Hui He
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, National United Engineering Laboratory of Functionalized Environmental Adsorption Materials, Soochow University, Suzhou, 215123, P. R. China
| | - Jian-Mei Lu
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, National United Engineering Laboratory of Functionalized Environmental Adsorption Materials, Soochow University, Suzhou, 215123, P. R. China
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11
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Liu D, Liu ZR, Wang ZH, Ma C, Herbert S, Schirok H, Mei TS. Paired electrolysis-enabled nickel-catalyzed enantioselective reductive cross-coupling between α-chloroesters and aryl bromides. Nat Commun 2022; 13:7318. [PMID: 36443306 PMCID: PMC9705544 DOI: 10.1038/s41467-022-35073-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/17/2022] [Indexed: 11/29/2022] Open
Abstract
Electrochemical asymmetric catalysis has emerged as a sustainable and promising approach to the production of chiral compounds and the utilization of both the anode and cathode as working electrodes would provide a unique approach for organic synthesis. However, precise matching of the rate and electric potential of anodic oxidation and cathodic reduction make such idealized electrolysis difficult to achieve. Herein, asymmetric cross-coupling between α-chloroesters and aryl bromides is probed as a model reaction, wherein alkyl radicals are generated from the α-chloroesters through a sequential oxidative electron transfer process at the anode, while the nickel catalyst is reduced to a lower oxidation state at the cathode. Radical clock studies, cyclic voltammetry analysis, and electron paramagnetic resonance experiments support the synergistic involvement of anodic and cathodic redox events. This electrolytic method provides an alternative avenue for asymmetric catalysis that could find significant utility in organic synthesis.
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Affiliation(s)
- Dong Liu
- grid.422150.00000 0001 1015 4378State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Zhao-Ran Liu
- grid.422150.00000 0001 1015 4378State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Zhen-Hua Wang
- grid.422150.00000 0001 1015 4378State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Cong Ma
- grid.422150.00000 0001 1015 4378State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Simon Herbert
- grid.420044.60000 0004 0374 4101Pharmaceuticals, Research and Development, Bayer AG, 13353 Berlin, Germany
| | - Hartmut Schirok
- grid.420044.60000 0004 0374 4101Pharmaceuticals, Research and Development, Bayer AG, 13353 Berlin, Germany
| | - Tian-Sheng Mei
- grid.422150.00000 0001 1015 4378State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, CAS, Shanghai, China
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12
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Wu X, Chang Y, Lin S. Titanium radical redox catalysis: Recent innovations in catalysts, reactions, and modes of activation. Chem 2022; 8:1805-1821. [DOI: 10.1016/j.chempr.2022.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Pellissier H. Recent developments in enantioselective titanium-catalyzed transformations. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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14
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Lustosa DM, Milo A. Mechanistic Inference from Statistical Models at Different Data-Size Regimes. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Danilo M. Lustosa
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Anat Milo
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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15
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Calogero F, Magagnano G, Potenti S, Pasca F, Fermi A, Gualandi A, Ceroni P, Bergamini G, Cozzi PG. Diastereoselective and enantioselective photoredox pinacol coupling promoted by titanium complexes with a red-absorbing organic dye. Chem Sci 2022; 13:5973-5981. [PMID: 35685797 PMCID: PMC9132033 DOI: 10.1039/d2sc00800a] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/21/2022] [Indexed: 12/12/2022] Open
Abstract
The pinacol coupling reaction, a reductive coupling of carbonyl compounds that proceeds through the formation of ketyl radicals in the presence of an electron donor, affords the corresponding 1,2-diols in one single step. The photoredox version of this transformation has been accomplished using different organic dyes or photoactive metal complexes in the presence of sacrificial donors such as tertiary amines or Hantzsch's ester. Normally, the homo-coupling of such reactive ketyl radicals is neither diastereo- nor enantio-selective. Herein, we report a highly diastereoselective pinacol coupling reaction of aromatic aldehydes promoted by 5 mol% of the non-toxic, inexpensive and available Cp2TiCl2 complex. The key feature that allows the complete control of diastereoselectivity is the employment of a red-absorbing organic dye in the presence of a redox-active titanium complex. Taking advantage of the well-tailored photoredox potential of this organic dye, the selective reduction of Ti(iv) to Ti(iii) is achieved. These conditions enable the formation of the d,l (syn) diastereoisomer as the favored product of the pinacol coupling (d.r. > 20 : 1 in most of the cases). Moreover, employing a simply prepared chiral SalenTi complex, the new photoredox reaction gave a complete diastereoselection for the d,l diastereoisomer, and high enantiocontrol (up to 92% of enantiomeric excess). A metallaphotoredox, diastereoselective and enantioselective pinacol coupling reaction promoted by titanium complexes with the use of a red-absorbing organic dye was developed.![]()
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Affiliation(s)
- Francesco Calogero
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Giandomenico Magagnano
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Simone Potenti
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Laboratorio SMART, Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa Italy
| | - Francesco Pasca
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Andrea Fermi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Andrea Gualandi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Paola Ceroni
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
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16
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Ding Z, Liu Z, Wang Z, Yu T, Xu M, Wen J, Yang K, Zhang H, Xu L, Li P. Catalysis with Diboron(4)/Pyridine: Application to the Broad-Scope [3 + 2] Cycloaddition of Cyclopropanes and Alkenes. J Am Chem Soc 2022; 144:8870-8882. [PMID: 35532758 DOI: 10.1021/jacs.2c03673] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In contrast to the extensive but non-recyclable use of tetraalkoxydiboron(4) compounds as stoichiometric reagents in diverse reactions, this article reports an atom-economical reaction using a commercial diboron(4) as the catalyst. The key to success was designing a catalytic cycle for radical [3 + 2] cycloaddition involving a pyridine cocatalyst to generate from the diboron(4) catalyst and reversibly mediate the transfer of boronyl radicals. In comparison with known [3 + 2] cycloaddition with transition metal-based catalysts, the current reaction features not only metal-free conditions, inexpensive and stable catalysts, and simple operation but also remarkably broadened substrate scope. In particular, previously unusable cyclopropyl ketones without an activating group and/or alkenes with 1,2-disubstitution and 1,1,2-trisubstitution patterns were successfully used for the first time. Consequently, challenging cyclopentane compounds with various levels of substitution (65 examples, 57 new products, up to six substituents at all five ring atoms) were readily prepared in generally high to excellent yield and diastereoselectivity. The reaction was also successfully applied in concise formal synthesis of an anti-obesity drug and building natural product-like complex bridged or spirocyclic compounds. Mechanistic experiments and computational investigation support the proposed radical relay catalysis featuring a pyridine-assisted boronyl radical catalyst. Overall, this work demonstrates the first approach to use tetraalkoxydiboron(4) compounds as catalysts and may lead to the development of new, green, and efficient transition metal-like boron-catalyzed organic reactions.
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Affiliation(s)
- Zhengwei Ding
- Department of Medicinal Chemistry, School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zhi Liu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
| | - Zhijun Wang
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi 832003, China
| | - Tao Yu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
| | - Ming Xu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
| | - Jingru Wen
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
| | - Kaiyan Yang
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
| | - Hailong Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Liang Xu
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi 832003, China
| | - Pengfei Li
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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17
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Hong P, Song X, Huang Z, Tan K, Wu A, Lu X. Insights into the Mechanism of Metal-Catalyzed Transformation of Oxime Esters: Metal-Bound Radical Pathway vs Free Radical Pathway. J Org Chem 2022; 87:6014-6024. [PMID: 35389656 DOI: 10.1021/acs.joc.2c00273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Controlling of radical reactivity by binding a radical to the metal center is an elegant strategy to overcome the challenge that radical intermediates are "too reactive to be selective". Yet, its application has seemingly been limited to a few strained-ring substrates, azide compounds, and diazo compounds. Meanwhile, first-row transition-metal-catalyzed (mainly, Fe, Ni, Cu) transformations of oxime esters have been reported recently in which the activation processes are assumed to follow free-radical mechanisms. In this work, we show by means of density functional theory calculations that the activation of oxime esters catalyzed by Fe(II) and Cu(I) catalysts more likely affords a metal-bound iminyl radical, rather than the presumed free iminyl radical, and the whole process follows a metal-bound radical mechanism. The as-formed metal-bound radical intermediates are an Fe(III)-iminyl radical (Stotal = 2, SFe = 5/2, and Siminyl = -1/2) and a Cu(II)-iminyl radical (Stotal = 0, SCu = 1/2, and Siminyl = -1/2). The discovery of such novel substrates affording metal-bound radical intermediates may facilitate the experimental design of metal-catalyzed asymmetric synthesis using oxime esters to achieve the desired enantioselectivity.
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Affiliation(s)
- Pan Hong
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaolin Song
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhengqi Huang
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kai Tan
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Anan Wu
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xin Lu
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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18
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Lauzon S, Schouwey L, Ollevier T. C2-Symmetric 2,2'-Bipyridine-α,α'-1-adamantyl-diol Ligand: Bulky Iron Complexes in Asymmetric Catalysis. Org Lett 2022; 24:1116-1120. [PMID: 35080897 DOI: 10.1021/acs.orglett.2c00141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of a chiral 2,2'-bipyridine-α,α'-1-adamantyl-diol ligand was achieved starting from commercially available materials. The bulky ligand was synthesized in three steps in 40% overall yield with stereoselectivities of 98% de and >99.5% ee for the S,S enantiomer. The absolute configuration of and structural insights into a heptacoordinated 2,2'-bipyridine-α,α'-1-Ad-diol/FeII chiral complex were obtained from single-crystal diffraction analyses. The newly synthesized ligand was used in iron-catalyzed asymmetric Mukaiyama aldol, thia-Michael, and Diels-Alder reactions.
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Affiliation(s)
- Samuel Lauzon
- Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6, Canada
| | - Lionel Schouwey
- Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6, Canada
| | - Thierry Ollevier
- Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6, Canada
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19
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Multinuclear Co(II) and Zn(II) salamo-based complexes with unique τ5 parameters: Structure characterizations, Hirshfeld surfaces and fluorescence properties. Polyhedron 2022. [DOI: 10.1016/j.poly.2021.115615] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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20
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Champagne PA. Identifying the true origins of selectivity in chiral phosphoric acid catalyzed N-acyl-azetidine desymmetrizations. Chem Sci 2021; 12:15662-15672. [PMID: 35003597 PMCID: PMC8654023 DOI: 10.1039/d1sc04969k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/10/2021] [Indexed: 01/01/2023] Open
Abstract
The first catalytic intermolecular desymmetrization of azetidines was reported by Sun and coworkers in 2015 using a BINOL-derived phosphoric acid catalyst (J. Am. Chem. Soc. 2015, 137, 5895-5898). To uncover the mechanism of the reaction and the origins of the high enantioselectivity, Density Functional Theory (DFT) calculations were performed at the B97D3/6-311+G(2d,2p)/SMD(toluene)//B97D3/6-31G(d,p)/CPCM(toluene) level of theory. Comparison of four possible activation modes confirms that this reaction proceeds through the bifunctional activation of the azetidine nitrogen and the thione tautomer of the 2-mercaptobenzothiazole nucleophile. Upon thorough conformational sampling of the enantiodetermining transition structures (TSs), a free energy difference of 2.0 kcal mol-1 is obtained, accurately reproducing the experimentally measured 88% e.e. at 80 °C. This energy difference is due to both decreased distortion and increased non-covalent interactions in the pro-(S) TS. To uncover the true origins of selectivity, the TSs optimized with the full catalyst were compared to those optimized with a model catalyst through steric maps. It is found that the arrangements displayed by the substrates are controlled by strict primary orbital interaction requirements at the transition complex, and their ability to fit into the catalyst pocket drives the selectivity. A general model of selectivity for phosphoric acid-catalyzed azetidine desymmetrizations is proposed, which is based on the preference of the nucleophile and benzoyl group to occupy empty quadrants of the chiral catalyst pocket.
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Affiliation(s)
- Pier Alexandre Champagne
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology Newark NJ USA
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21
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Riehl PS, Richardson AD, Sakamoto T, Reid JP, Schindler CS. Origin of enantioselectivity reversal in Lewis acid-catalysed Michael additions relying on the same chiral source. Chem Sci 2021; 12:14133-14142. [PMID: 34760198 PMCID: PMC8565382 DOI: 10.1039/d1sc03741b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/04/2021] [Indexed: 01/19/2023] Open
Abstract
Enantiodivergence is an important concept in asymmetric catalysis that enables access to both enantiomers of a product relying on the same chiral source as reagent. This strategy is particularly appealing as an alternate approach when only one enantiomer of the required chiral ligand is readily accessible but both enantiomers of the product are desired. Despite the potential significance, general catalytic methods to effectively reverse enantioselectivity by changing an achiral reaction parameter remain underdeveloped. Herein we report our studies focused on elucidating the origin of metal-controlled enantioselectivity reversal in Lewis acid-catalysed Michael additions. Rigorous experimental and computational investigations reveal that specific Lewis and Brønsted acid interactions between the substrate and ligand change depending on the ionic radius of the metal catalyst, and are key factors responsible for the observed enantiodivergence. This holds potential to further our understanding of and facilitate the design of future enantiodivergent transformations. Enantiodivergence is an important concept in asymmetric catalysis that enables access to both enantiomers of a product relying on the same chiral source as reagent.![]()
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Affiliation(s)
- Paul S Riehl
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor Michigan 48109 USA
| | - Alistair D Richardson
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor Michigan 48109 USA
| | - Tatsuhiro Sakamoto
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor Michigan 48109 USA
| | - Jolene P Reid
- Department of Chemistry, University of British Columbia 2036 Main Mall Vancouver British Columbia V6T 1Z1 Canada
| | - Corinna S Schindler
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan 930 North University Avenue Ann Arbor Michigan 48109 USA
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22
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Dhawa U, Wdowik T, Hou X, Yuan B, Oliveira JCA, Ackermann L. Enantioselective palladaelectro-catalyzed C-H olefinations and allylations for N-C axial chirality. Chem Sci 2021; 12:14182-14188. [PMID: 34760203 PMCID: PMC8565398 DOI: 10.1039/d1sc04687j] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/04/2021] [Indexed: 01/25/2023] Open
Abstract
Enantioselective palladaelectro-catalyzed C–H alkenylations and allylations were achieved with easily-accessible amino acids as transient directing groups. This strategy provided access to highly enantiomerically-enriched N–C axially chiral scaffolds under exceedingly mild conditions. The synthetic utility of our strategy was demonstrated by a variety of alkenes, while the versatility of our approach was reflected by atroposelective C–H allylations. Computational studies provided insights into a facile C–H activation by a seven-membered palladacycle. Enantioselective palladaelectro-catalyzed C–H alkenylations and allylations were achieved by the means of an easily-accessible amino acid for the synthesis of N–C axially chiral indole biaryls.![]()
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Affiliation(s)
- Uttam Dhawa
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Tomasz Wdowik
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Xiaoyan Hou
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Binbin Yuan
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - João C A Oliveira
- 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 .,Wöhler Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
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23
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SmI2-catalyzed intermolecular couplings by radical relay. TRENDS IN CHEMISTRY 2021. [DOI: 10.1016/j.trechm.2021.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Wang ZH, Gao PS, Wang X, Gao JQ, Xu XT, He Z, Ma C, Mei TS. TEMPO-Enabled Electrochemical Enantioselective Oxidative Coupling of Secondary Acyclic Amines with Ketones. J Am Chem Soc 2021; 143:15599-15605. [PMID: 34533943 DOI: 10.1021/jacs.1c08671] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An electrochemical asymmetric coupling of secondary acyclic amines with ketones via a Shono-type oxidation has been described, affording the corresponding amino acid derivatives with good to excellent diastereoselectivity and enantioselectivity. The addition of an N-oxyl radical as a redox mediator could selectively oxidize the substrate rather than the product, although their oxidation potential difference is subtle (about 13 mV). This electrochemical transformation proceeds in the absence of stoichiometric additives, including metals, oxidants, and electrolytes, which gives it good functional group compatibility. Mechanistic studies suggest that proton-mediated racemization of the product is prevented by the reduction of protons at the cathode.
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Affiliation(s)
- Zhen-Hua Wang
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Pei-Sen Gao
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Xiu Wang
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Jun-Qing Gao
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, People's Republic of China
| | - Xue-Tao Xu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, People's Republic of China
| | - Zeng He
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Cong Ma
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Tian-Sheng Mei
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
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25
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Passadis SS, Hadjithoma S, Siafarika P, Kalampounias AG, Keramidas AD, Miras HN, Kabanos TA. Synthesis, Structural and Physicochemical Characterization of a Titanium(IV) Compound with the Hydroxamate Ligand N,2-Dihydroxybenzamide. Molecules 2021; 26:5588. [PMID: 34577059 PMCID: PMC8465426 DOI: 10.3390/molecules26185588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 11/17/2022] Open
Abstract
The siderophore organic ligand N,2-dihydroxybenzamide (H2dihybe) incorporates the hydroxamate group, in addition to the phenoxy group in the ortho-position and reveals a very rich coordination chemistry with potential applications in medicine, materials, and physical sciences. The reaction of H2dihybe with TiCl4 in methyl alcohol and KOH yielded the tetranuclear titanium oxo-cluster (TOC) [TiIV4(μ-O)2(HOCH3)4(μ-Hdihybe)4(Hdihybe)4]Cl4∙10H2O∙12CH3OH (1). The titanium compound was characterized by single-crystal X-ray structure analysis, ESI-MS, 13C, and 1H NMR spectroscopy, solid-state and solution UV-Vis, IR vibrational, and luminescence spectroscopies and molecular orbital calculations. The inorganic core Ti4(μ-O)2 of 1 constitutes a rare structural motif for discrete TiIV4 oxo-clusters. High-resolution ESI-MS studies of 1 in methyl alcohol revealed the presence of isotopic distribution patterns which can be attributed to the tetranuclear clusters containing the inorganic core {Ti4(μ-O)2}. Solid-state IR spectroscopy of 1 showed the presence of an intense band at ~800 cm-1 which is absent in the spectrum of the H2dihybe and was attributed to the high-energy ν(Ti2-μ-O) stretching mode. The ν(C=O) in 1 is red-shifted by ~10 cm-1, while the ν(N-O) is blue-shifted by ~20 cm-1 in comparison to H2dihybe. Density Functional Theory (DFT) calculations reveal that in the experimental and theoretically predicted IR absorbance spectra of the ligand and Ti-complex, the main bands observed in the experimental spectra are also present in the calculated spectra supporting the proposed structural model. 1H and 13C NMR solution (CD3OD) studies of 1 reveal that it retains its integrity in CD3OD. The observed NMR changes upon addition of base to a CD3OD solution of 1, are due to an acid-base equilibrium and not a change in the TiIV coordination environment while the decrease in the complex's lability is due to the improved electron-donating properties which arise from the ligand deprotonation. Luminescence spectroscopic studies of 1 in solution reveal a dual narrow luminescence at different excitation wavelengths. The TOC 1 exhibits a band-gap of 1.98 eV which renders it a promising candidate for photocatalytic investigations.
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Affiliation(s)
- Stamatis S. Passadis
- Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece;
| | - Sofia Hadjithoma
- Department of Chemistry, University of Cyprus, Nicosia 2109, Cyprus;
| | - Panagiota Siafarika
- Physical Chemistry Laboratory, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece;
| | - Angelos G. Kalampounias
- Physical Chemistry Laboratory, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece;
- Institute of Materials Science and Computing, University Research Center of Ioannina (URCI), 45110 Ioannina, Greece
| | | | | | - Themistoklis A. Kabanos
- Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece;
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26
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A family of salamo-type trinuclear Co(II) and Ni(II) complexes: Structural characterization, Hirshfeld surface analysis and fluorescent properties. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115267] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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27
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Xiao X, Yu ZX. Co-Catalyzed Asymmetric Intramolecular [3+2] Cycloaddition of Yne-Alkylidenecyclopropanes and its Reaction Mechanism. Chemistry 2021; 27:7176-7182. [PMID: 33554413 DOI: 10.1002/chem.202100426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Indexed: 11/08/2022]
Abstract
Developing new transition metal-catalyzed asymmetric cycloadditions for the synthesis of five-membered carbocycles (FMCs) is a research frontier in reaction development due to the ubiquitous presence of chiral FMCs in various functional molecules. Reported here is our discovery of a highly enantioselective intramolecular [3+2] cycloaddition of yne-alkylidenecyclopropanes (yne-ACPs) to bicyclo[3.3.0]octadiene and bicyclo[4.3.0]nonadiene molecules using a cheap Co catalyst and commercially available chiral ligand (S)-Xyl-BINAP. This reaction avoids the use of precious Pd and Rh catalysts, which are usually the choices for [3+2] reactions with ACPs. The enantiomeric excess in the present reaction can be up to 92 %. Cationic cobalt(I) species was suggested by experiments as the catalytic species. DFT calculations showed that this [3+2] reaction starts with oxidative cyclometallation of alkyne and ACP, followed by ring opening of the cyclopropyl (CP) group and reductive elimination to form the cycloadduct. This mechanism is different from previous [3+2] reactions of ACPs, which usually start from CP cleavage, not from oxidative cyclization.
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Affiliation(s)
- Xiong Xiao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular, Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China
| | - Zhi-Xiang Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular, Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China
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28
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Agasti S, Beattie NA, McDouall JJW, Procter DJ. SmI 2-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity. J Am Chem Soc 2021; 143:3655-3661. [PMID: 33629852 PMCID: PMC8028054 DOI: 10.1021/jacs.1c01356] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The archetypal single electron transfer reductant, samarium(II) diiodide (SmI2, Kagan's reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI2 is very often unique, and thus the reagent is indispensable, it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI2, all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II). Here, we describe a SmI2-catalyzed intermolecular radical coupling of aryl cyclopropyl ketones and alkynes. The process shows broad substrate scope and delivers a library of decorated cyclopentenes with loadings of SmI2 as low as 15 mol %. The radical relay strategy negates the need for a superstoichiometric coreductant and additives to regenerate SmI2. Crucially, our study uncovers an intriguing link between ketone conformation and efficient cross-coupling and thus provides an insight into the mechanism of radical relays involving SmI2. The study lays further groundwork for the future use of the classical reagent SmI2 in contemporary radical catalysis.
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Affiliation(s)
- Soumitra Agasti
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Nicholas A Beattie
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Joseph J W McDouall
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - David J Procter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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29
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Li Y, Chen F, Zhu S, Chu L. Photoinduced triiodide-mediated [3 + 2] cycloaddition of N-tosyl aziridines and alkenes. Org Chem Front 2021. [DOI: 10.1039/d1qo00102g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A photoinduced triiodide-mediated [3 + 2] cycloaddition of N-Ts aziridines and alkenes is described herein. This operationally simple protocol enables regioselective access to a wide range of substituted pyrrolidines under mild-free conditions.
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Affiliation(s)
- Yuanbo Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- Center for Advanced Low-Dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - Fan Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- Center for Advanced Low-Dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - Shengqing Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- Center for Advanced Low-Dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - Lingling Chu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- Center for Advanced Low-Dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
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