1
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Bao J, Nick SJ, Lanin AS, Iragorri Molinero N, Sera BJ, Njardarson JT. Stereoselective Synthesis of Conjugated Di- and Trienamides via a Dienolate Enabled Anionic Cascade. J Org Chem 2023. [PMID: 38048698 DOI: 10.1021/acs.joc.3c02327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
We report a stereoselective synthesis of conjugated di- and trienamides from the direct one pot γ-selective union of a dienolate and chiral nonconjugated and conjugated sulfinyl imines, respectively. This class of anionic cascades was uncovered as part of efforts to challenge the steric limitations of an anionic asymmetric amino-Cope rearrangement platform. Reaction scope studies have uncovered the substitution patterns essential for starting chiral tri- and Z-disubstituted conjugated and nonconjugated sulfinyl imines to be matched for the anionic cascade. Mechanistic studies indicate that, following an initial γ-dienolate Mannich attack, an intermediate 5,6-dihydropyridin-2(1H)-one is formed and then ring-opened.
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Affiliation(s)
- Jianhua Bao
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Steven J Nick
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Aleksey S Lanin
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Nerea Iragorri Molinero
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Brendon J Sera
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jon T Njardarson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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2
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Ma N, Zhou L, Li Y, Wu H, Li S, Zhang G. Theoretical Insight into the Mechanism of Cu(I)-Catalyzed [2 + 2 + 1] Cycloaddition to β-Pyrrolinones: Azaheterocycle Formation and Assisted Dehydrogenation with Solvent MeNO 2. J Org Chem 2023. [PMID: 37467204 DOI: 10.1021/acs.joc.3c00727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
The construction of multisubstituted β-pyrrolinones from simple starting materials remains a great challenge. Recently, a novel Cu(I)-catalyzed [2 + 2 + 1] cycloaddition reaction was developed for rapid access to fully substituted β-pyrrolinones, which are difficult to synthesize through traditional methods as this approach may involve unusual C-nucleophilic addition of enamines and umpolung of imines. Elucidating the reaction mechanism may inspire the development of new methodologies via the unusual C-nucleophilic addition of enamines and imines. However, the reaction mechanism is still unclear because none of the intermediates was observed during the reaction process. In this work, we employed theoretical and computational chemistry to investigate the possible pathway. Finally, the calculated results indicate that ketene formed by the Wolff rearrangement of α-diazo-β-ketoester reacts with enamine formed by the addition of alkynes and amine, affording the five-membered azaheterocycle, and this process involves the formation of a six-membered ring intermediate and sequential isomerization, and the further dehydrogenation needs to be assisted with solvent MeNO2.
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Affiliation(s)
- Nana Ma
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Lanxin Zhou
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Yameng Li
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Hao Wu
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Shujun Li
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Guisheng Zhang
- School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Normal University, Xinxiang, Henan, 453007, China
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3
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Azaz T, Mourya H, Singh V, Ram B, Tiwari B. N-Heterocyclic Carbene-Catalyzed Enantioselective [3 + 2] Annulation of Enals with Vinyl Ketones. J Org Chem 2023; 88:1219-1226. [PMID: 36622160 DOI: 10.1021/acs.joc.2c01894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
An unprecedented N-heterocyclic carbene (NHC)-catalyzed enantioselective [3 + 2] annulation of enals with vinyl ketones has been achieved. Unlike chalcones, the β-unsubstituted enones, namely, vinyl ketones, have remained challenging in terms of reactivity, especially enantioselectivity. The disubstituted cyclopentenes were obtained in good yields and excellent stereoselectivities in the presence of Ti(OiPr)4.
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Affiliation(s)
- Tazeen Azaz
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow, Uttar Pradesh 226014, India.,Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India
| | - Hemlata Mourya
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow, Uttar Pradesh 226014, India
| | - Vikram Singh
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow, Uttar Pradesh 226014, India.,Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India
| | - Bali Ram
- Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India
| | - Bhoopendra Tiwari
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow, Uttar Pradesh 226014, India
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4
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Groch JR, Lauta NR, Njardarson JT. One Step Selective Counterion Dependent Formation of Conjugated Chiral N-Sulfinylimines from Aldehydes. Org Lett 2023; 25:395-399. [PMID: 36603180 DOI: 10.1021/acs.orglett.2c04102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We report a detailed study on the synthesis and aldehyde vinylogation applications of chiral N-sulfinyl imine phosphonate reagents. Two complementary scalable reagent routes, from trialkyl phosphites and methyl phosphonates, respectively, are presented. This reagent class enables significant streamlining in synthesis of conjugated Ellman imines from aldehydes, which can now be accomplished in a single step compared to a more classic 4-step redox-based approach. Aldehyde vinylogation optimizations have revealed significant counterion effects and unexpected competing reaction challenges that needed to be addressed to achieve high yields.
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Affiliation(s)
- Jeffrey R Groch
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Nicholas R Lauta
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jon T Njardarson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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5
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Qureshi MH, Njardarson JT. Anionic Amino-Cope Rearrangement Cascade Synthesis of 2,4-Substituted Benzoate Esters from Acyclic Building Blocks. Org Lett 2022; 24:7978-7982. [PMID: 36268999 DOI: 10.1021/acs.orglett.2c03134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a new anionic cascade for assembling 2,4-substituted benzoate esters in one pot from racemic β-fluoro-substituted conjugated tert-butylsulfinyl imines and 3-substituted methyl 2-butenoates. Dienolate formation triggers a Mannich addition followed by an amino-Cope like rearrangement, which results in immediate elimination of fluoride by a lithiated enamine. The newly formed 1,4-diene intermediate contains a highly acidic proton which is spontaneously deprotonated, leading to a facile intramolecular cyclization followed by sulfinamide group elimination and aromatization.
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Affiliation(s)
- M Haziq Qureshi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jon T Njardarson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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6
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Yanagi T, Yorimitsu H. Mechanistic Investigation of a Synthetic Route to Biaryls by the Sigmatropic Rearrangement of Arylsulfonium Species. Chemistry 2021; 27:13450-13456. [PMID: 34322930 DOI: 10.1002/chem.202101735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Indexed: 12/26/2022]
Abstract
A comprehensive mechanistic investigation was conducted on the coupling reaction of aryl sulfoxides with phenols by using trifluoroacetic anhydride to yield biaryls. NMR experiments revealed that our previously proposed mechanism, which consists of a cascade of an interrupted Pummerer reaction and a rate-determining [3,3] sigmatropic rearrangement, is reasonable. The electronic effects of the substrates were also evaluated to elucidate the nature of the rearrangement step. Based on experimental observations and theoretical calculations, we conclude that the rearrangement is highly asynchronous and stepwise rather than concerted when electron-rich phenols are employed for the reaction.
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Affiliation(s)
- Tomoyuki Yanagi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Hideki Yorimitsu
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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7
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Alabugin IV, Kuhn L, Medvedev MG, Krivoshchapov NV, Vil' VA, Yaremenko IA, Mehaffy P, Yarie M, Terent'ev AO, Zolfigol MA. Stereoelectronic power of oxygen in control of chemical reactivity: the anomeric effect is not alone. Chem Soc Rev 2021; 50:10253-10345. [PMID: 34263287 DOI: 10.1039/d1cs00386k] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although carbon is the central element of organic chemistry, oxygen is the central element of stereoelectronic control in organic chemistry. Generally, a molecule with a C-O bond has both a strong donor (a lone pair) and a strong acceptor (e.g., a σ*C-O orbital), a combination that provides opportunities to influence chemical transformations at both ends of the electron demand spectrum. Oxygen is a stereoelectronic chameleon that adapts to the varying situations in radical, cationic, anionic, and metal-mediated transformations. Arguably, the most historically important stereoelectronic effect is the anomeric effect (AE), i.e., the axial preference of acceptor groups at the anomeric position of sugars. Although AE is generally attributed to hyperconjugative interactions of σ-acceptors with a lone pair at oxygen (negative hyperconjugation), recent literature reports suggested alternative explanations. In this context, it is timely to evaluate the fundamental connections between the AE and a broad variety of O-functional groups. Such connections illustrate the general role of hyperconjugation with oxygen lone pairs in reactivity. Lessons from the AE can be used as the conceptual framework for organizing disjointed observations into a logical body of knowledge. In contrast, neglect of hyperconjugation can be deeply misleading as it removes the stereoelectronic cornerstone on which, as we show in this review, the chemistry of organic oxygen functionalities is largely based. As negative hyperconjugation releases the "underutilized" stereoelectronic power of unshared electrons (the lone pairs) for the stabilization of a developing positive charge, the role of orbital interactions increases when the electronic demand is high and molecules distort from their equilibrium geometries. From this perspective, hyperconjugative anomeric interactions play a unique role in guiding reaction design. In this manuscript, we discuss the reactivity of organic O-functionalities, outline variations in the possible hyperconjugative patterns, and showcase the vast implications of AE for the structure and reactivity. On our journey through a variety of O-containing organic functional groups, from textbook to exotic, we will illustrate how this knowledge can predict chemical reactivity and unlock new useful synthetic transformations.
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Affiliation(s)
- Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Leah Kuhn
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Michael G Medvedev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.,A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova St., 119991 Moscow, Russian Federation
| | - Nikolai V Krivoshchapov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.,Lomonosov Moscow State University, Leninskie Gory 1 (3), Moscow, 119991, Russian Federation
| | - Vera A Vil'
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Ivan A Yaremenko
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Patricia Mehaffy
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Meysam Yarie
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65167, Iran
| | - Alexander O Terent'ev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Mohammad Ali Zolfigol
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65167, Iran
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8
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Scott KA, Groch JR, Chogii I, Delost MD, Das P, Njardarson JT. Dienolate Annulation Approach for Assembly of Densely Substituted Aromatic Architectures. J Org Chem 2021; 86:10555-10567. [PMID: 34283591 DOI: 10.1021/acs.joc.1c01211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The efficient assembly of complex aromatic structures from simple acyclic building blocks is reported. An anion-cascade union of an enoate and a conjugated imine affords cyclohexenone products, which are readily aromatized to phenols. By engaging the intermediate cyclohexenones with Grignard reagents, a facile addition/elimination proceeds yielding chiral cyclohexadienes, which are then aromatized. In a complementary approach, the cyclohexenone products are converted into enol triflates, which provides a gateway to diverse aromatic architectures following cross-couplings and aromatization steps.
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9
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Das P, Delost MD, Qureshi MH, Bao J, Fell JS, Houk KN, Njardarson JT. Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades. J Am Chem Soc 2021; 143:5793-5804. [PMID: 33844522 DOI: 10.1021/jacs.1c00745] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We report a dramatic effect on product outcomes of the lithium ion enabled amino-Cope-like anionic asymmetric cascade when different γ-dienolate heteroatom substituents are employed. For dienolates with azide, thiomethyl, and trifluoromethylthiol substituents, a Mannich/amino-Cope/cyclization cascade ensues to form chiral cyclohexenone products with two new stereocenters in an anti-relationship. For fluoride-substituted nucleophiles, a Mannich/amino-Cope cascade proceeds to afford chiral acyclic products with two new stereocenters in a syn-relationship. Bromide- and chloride-substituted nucleophiles appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent, with a lithium counterion being essential in combination with etheral solvents such as MTBE and CPME. By altering the geometry of the imine double bond from E to Z, the configurations at the R1 and X stereocenters are flipped. Mechanistic, computational, substituent, and counterion studies suggest that these cascades proceed via a common Mannich-product intermediate, which then proceeds via either a chair (X = N3, SMe, or SCF3) or boat-like (X = F, Cl, or Br) transition state to afford amino-Cope-like products or β-lactam in the case of X = NO2.
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Affiliation(s)
- Pradipta Das
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Michael D Delost
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Munaum H Qureshi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jianhua Bao
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jason S Fell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Jon T Njardarson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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10
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Wu H, Li X, Yan Z, Ma N, Song S, Zhang G, Jiao N. Cu(I)-Catalyzed [2 + 2 + 1] Cycloaddition of Amines, Alkynes, and Ketenes: An Umpolung and Regioselective Approach to Full-Substituted β-Pyrrolinones. Org Lett 2021; 23:762-766. [PMID: 33443435 DOI: 10.1021/acs.orglett.0c03991] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Described here is a Cu-catalyzed [2 + 2 + 1] modular synthesis of full-substituted β-pyrrolinones from simple amines, alkynes, and α-diazo-β-ketoesters. This approach involving the regioselective C-nucleophilic attack of enamines, uncommon C-nucleophilic addition to ketenes, and umpolung of imines enables the direct synthesis of full-substituted β-pyrrolinones, which were hardly constructed by traditional synthetic strategies.
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Affiliation(s)
- Hao Wu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.,State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Xinyao Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Zixi Yan
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Nana Ma
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Song Song
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Guisheng Zhang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Ning Jiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
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11
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Hu J, Yang X, Shi S, Cheng B, Luo X, Lan Y, Loh TP. Metal-free C(sp 3)-H functionalization of sulfonamides via strain-release rearrangement. Chem Sci 2021; 12:4034-4040. [PMID: 34163674 PMCID: PMC8179522 DOI: 10.1039/d0sc06603f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/17/2021] [Indexed: 11/21/2022] Open
Abstract
With the increasing awareness of sustainable chemistry principles, the development of an efficient and mild strategy for C(sp3)-H bond activation of nitrogen-containing compounds without the utilization of any oxidant and metal is still highly desired and challenging. Herein, we present a metal-free reaction system that enables C-H bond functionalization of aliphatic sulfonamides using DABCO as a promoter under mild conditions, affording a series of α,β-unsaturated imines in good yields with high selectivities. This protocol tolerates a broad range of functionalities and can serve as a powerful synthetic tool for the late-stage modification of complex compounds. More importantly, control experiments and detailed DFT calculations suggest that this process involves [2 + 2] cyclization/ring-cleavage reorganization, which opens up a new platform for the establishment of other related reorganization reactions.
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Affiliation(s)
- Jiefeng Hu
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University Nanjing 211816 China
| | - Xianyu Yang
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University Nanjing 211816 China
| | - Shasha Shi
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University Nanjing 211816 China
| | - Bo Cheng
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University Nanjing 211816 China
| | - Xiaoling Luo
- Chongqing Key Laboratory of Inorganic Functional Materials, College of Chemistry, Chongqing Normal University Chongqing 401331 China
| | - Yu Lan
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University Zhengzhou Henan 450001 China
| | - Teck-Peng Loh
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University Nanjing 211816 China
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
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12
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Pareek M, Sunoj RB. Mechanistic insights into rhodium-catalyzed enantioselective allylic alkylation for quaternary stereogenic centers. Chem Sci 2020; 12:2527-2539. [PMID: 34164021 PMCID: PMC8179253 DOI: 10.1039/d0sc04959j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Installing quaternary stereogenic carbon is an arduous task of contemporary importance in the domain of asymmetric catalysis. To this end, an asymmetric allylic alkylation of α,α-disubstituted aldehydes by using allyl benzoate in the presence of Wilkinson's catalyst [Rh(Cl)(PPh3)3], (R)-BINOL–P(OMe) as the external ligand, and LiHMDS as the base has been reported to offer high enantioselectivity. The mechanistic details of this important reaction remain vague, which prompted us to undertake a detailed density functional theory (SMD(THF)/B3LYP-D3) investigation on the nature of the potential active catalyst, energetic features of the catalytic cycle, and the origin of high enantioselectivity. We note that a chloride displacement from the native Rh-phosphine [Rh(Cl)(PPh3)3] by BINOL–P(OMe) phosphite and an ensuing MeCl elimination can result in the in situ formation of a Rh-phosphonate [Rh(BINOL–P
Created by potrace 1.16, written by Peter Selinger 2001-2019
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O)(PPh3)3]. A superior energetic span (δE) noted with such a Rh-phosphonate suggests that it is likely to serve as an active catalyst. The uptake of allyl benzoate by the active catalyst followed by the turnover determining C–O bond oxidative addition furnishes a Rh-π-allyl intermediate, which upon interception by (Z)-Li-enolate (derived from α,α-disubstituted aldehyde) in the enantiocontrolling C–C bond generates a quaternary stereogenic center. The addition of the re prochiral face of the (Z)-Li-enolate to the Rh-bound allyl moiety leading to the R enantiomer of the product is found to be 2.4 kcal mol−1 more preferred over the addition through its si face. The origin of the stereochemical preference for the re face addition is traced to improved noncovalent interactions (NCIs) and less distortion in the enantiocontrolling C–C bond formation transition state than that in the si face addition. Computed enantioselectivity (96%) is in very good agreement with the experimental value (92%), so is the overall activation barrier (δE of 17.1 kcal mol−1), which is in conformity with room temperature reaction conditions. The origin of high enantioselectivity in the formation of quaternary stereogenic carbon.![]()
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Affiliation(s)
- Monika Pareek
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
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13
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Verma RS, Mishra M, Pandey CB, Kumar S, Tiwari B. Global Access to 3/4-Phosphorylated Heterocycles via a Carbene-Catalyzed Stetter Reaction of Vinylphosphonates and Aldehydes. J Org Chem 2020; 85:8166-8175. [DOI: 10.1021/acs.joc.0c00150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ram Subhawan Verma
- Division of Molecular Synthesis & Drug Discovery, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Monika Mishra
- Division of Molecular Synthesis & Drug Discovery, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Chandra Bhan Pandey
- Division of Molecular Synthesis & Drug Discovery, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Shailesh Kumar
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Bhoopendra Tiwari
- Division of Molecular Synthesis & Drug Discovery, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
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14
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Wylie L, Flynn M, Blair VL, Andrews PC, Izgorodina EI. Isomers of Alkali Metal (Methylbenzyl)allylamides: A Theoretical Perspective. ACS OMEGA 2020; 5:9448-9457. [PMID: 32363297 PMCID: PMC7191839 DOI: 10.1021/acsomega.0c00652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
Recent studies of alkali metal N-(α-methylbenzyl)allylamides containing lithium, sodium, and potassium have shown unique rearrangements in NMR experiments. It was found that lithium isomers favored the formation of aza-allyl and aza-enolate complexes that could exist in a solution for a substantial amount of time. As the radius of the metal ion increases going from lithium to potassium, so does the preference for the formation of the imine structure. For sodium, the aza-allyl complex could still be isolated, whereas the imine structure was only found to be stable on the scale of several hours for potassium. In this work, ab initio calculations were used to shed light on this phenomenon. Decomposition of intermolecular interaction energies of the aza-allyl, aza-enolate, and imine complexes showed that for lithium, the formation of aza-allyl and aza-enolate complexes was driven by electrostatic interactions. For potassium, the dispersion component of the metal interaction with the ligand proved to be more important for the stability of the imine structure. The presence of the imine formation in potassium and partially in sodium was found to be due to the reduced electrostatic nature of these larger metals. The assignment of the experimental NMR spectra was further confirmed with the natural bond order (NBO) analysis as well as the partial charge calculations. Analysis of orbital energies, specifically those of the highest occupied molecular orbitals (HOMOs), as well as the deformation energies of each of the ligands, were also considered. Through these procedures, an understanding of the tendency for each metal to have a unique isomerization pathway was gained.
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Ramaiah MM, Shubha PB, Prabhala PK, Shivananju NS. 1,8-Diazabicyclo[5.4.0]undec-7-ene-mediated formation of N-sulfinyl imines. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.1177/1747519819884146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A facile and efficient method was developed for the preparation of a variety of aryl, heteroaryl, and alkyl N-sulfinyl imines using 1,8-diazabicyclo[5.4.0]undec-7-ene. In addition to tert-butanesulfinamide, the condensation is also effective with p-toluenesulfinamide. The reaction was performed at room temperature and produces the corresponding N-sulfinyl imines in excellent yields in the absence of acids, metals, and additives. This methodology is also useful for the preparation of N-sulfinyl imines on gram scale. A one-pot synthesis was developed using aryl and heteroaryl alcohols with both tert-butanesulfinamide and p-toluenesulfinamide at room temperature, resulting in the corresponding N-sulfinyl imines with good yields.
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Affiliation(s)
- Manjunatha M Ramaiah
- Synthetic Laboratory, Department of Studies in Chemistry, University of Mysore, Mysore, India
| | - Priya Babu Shubha
- Synthetic Laboratory, Department of Studies in Chemistry, University of Mysore, Mysore, India
| | - Pavan Kumar Prabhala
- Department of Chemistry, S.V.R.M. College, Acharya Nagarjuna University, Guntur, India
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Li CT, Liu H, Yao Y, Lu CD. Rearrangement of N- tert-Butanesulfinyl Enamines for Synthesis of Enantioenriched α-Hydroxy Ketone Derivatives. Org Lett 2019; 21:8383-8388. [PMID: 31592671 DOI: 10.1021/acs.orglett.9b03159] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Treating chiral N-tert-butanesulfinyl ketimines with potassium hexamethyldisilazide (or potassium tert-butoxide) and methyl triflate gives N-methylated N-tert-butanesulfinyl enamine intermediates that undergo stereoselective [2,3]-rearrangement to afford α-sulfenyloxy ketones with excellent enantiopurities. This cascade of enamination-N-methylation-rearrangement was even used to generate acyclic tertiary α-hydroxy ketones bearing two α-substituents showing negligible differences in bulkiness, such as methyl and ethyl groups.
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Affiliation(s)
- Chun-Tian Li
- Xinjiang Technical Institute of Physics & Chemistry , Chinese Academy of Sciences , Urumqi 830011 , China
| | - Hui Liu
- Xinjiang Technical Institute of Physics & Chemistry , Chinese Academy of Sciences , Urumqi 830011 , China
| | - Yun Yao
- School of Chemical Science and Technology , Yunnan University , Kunming 650091 , China
| | - Chong-Dao Lu
- School of Chemical Science and Technology , Yunnan University , Kunming 650091 , China
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Hudwekar AD, Verma PK, Kour J, Balgotra S, Sawant SD. Transition Metal-Free Oxidative Coupling of Primary Amines in Polyethylene Glycol at Room Temperature: Synthesis of Imines, Azobenzenes, Benzothiazoles, and Disulfides. European J Org Chem 2019. [DOI: 10.1002/ejoc.201801610] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Abhinandan D. Hudwekar
- Medicinal Chemistry Division; CSIR-Indian Institute of Integrative Medicine; Canal Road -180001 Jammu India
- Anusandhan Bhawan; Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg 110001 New Delhi India
| | - Praveen K. Verma
- Medicinal Chemistry Division; CSIR-Indian Institute of Integrative Medicine; Canal Road -180001 Jammu India
| | - Jaspreet Kour
- Medicinal Chemistry Division; CSIR-Indian Institute of Integrative Medicine; Canal Road -180001 Jammu India
- Anusandhan Bhawan; Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg 110001 New Delhi India
| | - Shilpi Balgotra
- Medicinal Chemistry Division; CSIR-Indian Institute of Integrative Medicine; Canal Road -180001 Jammu India
- Anusandhan Bhawan; Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg 110001 New Delhi India
| | - Sanghapal D. Sawant
- Medicinal Chemistry Division; CSIR-Indian Institute of Integrative Medicine; Canal Road -180001 Jammu India
- Anusandhan Bhawan; Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg 110001 New Delhi India
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Angello NH, Wiley RE, Elmore TG, Perry RS, Scheerer JR. Domino Reaction Sequence for the Synthesis of [2.2.2]Diazabicycloalkenes and Base-Promoted Cycloreversion to 2-Pyridone Alkaloids. Org Lett 2018; 20:5203-5207. [PMID: 30095269 PMCID: PMC6220673 DOI: 10.1021/acs.orglett.8b02145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new domino reaction sequence for the construction of 2-pyridone structures is reported. The reaction sequence begins with diacetyldiketopiperazine and proceeds via aldol condensation, alkene isomerization, and intramolecular Diels-Alder cycloaddition. The intermediate [2.2.2]diazabicycloalkene cycloadducts can be isolated or can engage in a base-accelerated extrusion of one lactam bridge to provide the 2-pyridone cycloreversion products. The operation leading to pyridone products can occur in one reaction vessel and proceeds at convenient temperatures.
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Affiliation(s)
- Nicholas H. Angello
- Department of Chemistry, The College of William & Mary, P.O. Box 8795, Williamsburg, Virginia 23187, United States
| | - Robert E. Wiley
- Department of Chemistry, The College of William & Mary, P.O. Box 8795, Williamsburg, Virginia 23187, United States
| | - Tristan G. Elmore
- Department of Chemistry, The College of William & Mary, P.O. Box 8795, Williamsburg, Virginia 23187, United States
| | - Ryan S. Perry
- Department of Chemistry, The College of William & Mary, P.O. Box 8795, Williamsburg, Virginia 23187, United States
| | - Jonathan R. Scheerer
- Department of Chemistry, The College of William & Mary, P.O. Box 8795, Williamsburg, Virginia 23187, United States
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Chogii I, Das P, Delost MD, Crawford MN, Njardarson JT. Asymmetric Vinylogous Aza-Darzens Approach to Vinyl Aziridines. Org Lett 2018; 20:4942-4945. [DOI: 10.1021/acs.orglett.8b02074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Isaac Chogii
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Pradipta Das
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Michael D. Delost
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Mark N. Crawford
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jon T. Njardarson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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