1
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Breuers CBJ, Daniliuc CG, Studer A. Oxidative N-Heterocyclic Carbene-Catalyzed Intramolecular Friedel-Crafts Alkylation of Indoles for the Synthesis of Spirocyclic Indolenines. Org Lett 2022; 24:5314-5318. [PMID: 35834420 DOI: 10.1021/acs.orglett.2c01927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The stereoselective intramolecular dearomatizing spirocyclization of indoles via oxidative N-heterocyclic carbene (NHC) catalysis to afford indolenines bearing an all-carbon quaternary center at the 3-position is reported. The reaction proceeds via the intramolecular nucleophilic addition of the indole to an in situ generated α,β-unsaturated acyl azolium. The cyclized indolenine bearing an acyl azolium functionality is trapped by a suitable external nucleophile that does not efficiently react with the α,β-unsaturated acyl azolium via direct acylation.
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Affiliation(s)
- Christian B J Breuers
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, Münster, North Rhine-Westphalia 48149, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, Münster, North Rhine-Westphalia 48149, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, Münster, North Rhine-Westphalia 48149, Germany
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2
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Golub TP, Merten C. Vibrational CD study on the solution phase structures of the MacMillan catalyst and its corresponding iminium ion. Phys Chem Chem Phys 2021; 23:25162-25169. [PMID: 34730148 DOI: 10.1039/d1cp04497d] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We demonstrate that VCD spectroscopy can reveal insights into the conformational preferences of the iminium ion obtained from MacMillan's imidazolidinone catalyst. For both the isolated and in situ generated iminium ion, the comparison of experimental and computed VCD spectra directly confirms that conformer 2b ("Houk-conformer") is the dominant structure in solution. This conclusion is reached without any in-depth interpretation of the spectroscopic data, just by visual comparison of the spectral signatures. For the parent catalyst 1 and its salts 1·HCl and 1·HClO4, we report a comprehensive analysis of the conformational preferences in two solvents. VCD spectroscopy is subsequently shown to be able to reveal small conformational changes induced by solute-solvent and solute-anion interactions.
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Affiliation(s)
- Tino P Golub
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
| | - Christian Merten
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
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3
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Zhang J, Chen Q, Mayer RJ, Yang J, Ofial AR, Cheng J, Mayr H. Predicting Absolute Rate Constants for Huisgen Reactions of Unsaturated Iminium Ions with Diazoalkanes. Angew Chem Int Ed Engl 2020; 59:12527-12533. [PMID: 32259362 PMCID: PMC7383640 DOI: 10.1002/anie.202003029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Indexed: 12/22/2022]
Abstract
The kinetics and stereochemistry of the reactions of iminium ions derived from cinnamaldehydes and MacMillan's imidazolidinones with diphenyldiazomethane and aryldiazomethanes were investigated experimentally and with DFT calculations. The reactions of diphenyldiazomethane with iminium ions derived from MacMillan's second-generation catalysts gave 3-aryl-2,2-diphenylcyclopropanecarbaldehydes with yields >90 % and enantiomeric ratios of ≥90:10. Predominantly 2:1 products were obtained from the corresponding reactions with monoaryldiazomethanes. The measured rate constants are in good agreement with the rate constants derived from the one-center nucleophilicity parameters N and sN of diazomethanes and the one-center electrophilicity parameters E of iminium ions as well as with quantum chemically calculated activation energies.
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Affiliation(s)
- Jingjing Zhang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Quan Chen
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Robert J. Mayer
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Jin‐Dong Yang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Armin R. Ofial
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Jin‐Pei Cheng
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
- State Key Laboratory of Elemento-organic ChemistryCollege of ChemistryNankai UniversityTianjin300071P. R. China
| | - Herbert Mayr
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
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4
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Zhang J, Chen Q, Mayer RJ, Yang J, Ofial AR, Cheng J, Mayr H. Voraussage absoluter Geschwindigkeitskonstanten von Huisgen‐ Reaktionen ungesättigter Iminium‐Ionen mit Diazoalkanen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Jingjing Zhang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 VR China
| | - Quan Chen
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Deutschland
| | - Robert J. Mayer
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Deutschland
| | - Jin‐Dong Yang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 VR China
| | - Armin R. Ofial
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Deutschland
| | - Jin‐Pei Cheng
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 VR China
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 VR China
| | - Herbert Mayr
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Deutschland
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5
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Mood A, Tavakoli M, Gutman E, Kadish D, Baldi P, Van Vranken DL. Methyl Anion Affinities of the Canonical Organic Functional Groups. J Org Chem 2020; 85:4096-4102. [PMID: 31995384 DOI: 10.1021/acs.joc.9b03187] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Calculated methyl anion affinities are known to correlate with experimentally determined Mayr E parameters for individual organic functional group classes but not between neutral and cationic organic electrophiles. We demonstrate that methyl anion affinities calculated with a solvation model (MAA*) give a linear correlation with Mayr E parameters for a broad range of functional groups. Methyl anion affinities (MAA*), plotted on the log scale of Mayr E, provide insights into the full range of electrophilicity of organic functional groups. On the Mayr E scale, the electrophilicity toward the methyl anion spans 180 orders of magnitude.
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Affiliation(s)
- Aaron Mood
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Mohammadamin Tavakoli
- Department of Computer Science, University of California Irvine, Irvine, California 92697, United States
| | - Eugene Gutman
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Dora Kadish
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Pierre Baldi
- Department of Computer Science, University of California Irvine, Irvine, California 92697, United States
| | - David L Van Vranken
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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6
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An F, Maji B, Min E, Ofial AR, Mayr H. Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts. J Am Chem Soc 2020; 142:1526-1547. [DOI: 10.1021/jacs.9b11877] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Feng An
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Biplab Maji
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Elizabeth Min
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Armin R. Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
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7
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Cozzi PG, Gualandi A, Potenti S, Calogero F, Rodeghiero G. Asymmetric Reactions Enabled by Cooperative Enantioselective Amino- and Lewis Acid Catalysis. Top Curr Chem (Cham) 2019; 378:1. [PMID: 31761979 DOI: 10.1007/s41061-019-0261-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 10/22/2019] [Indexed: 01/04/2023]
Abstract
Organocatalysis-the branch of catalysis featuring small organic molecules as the catalysts-has, in the last decade, become of central importance in the field of asymmetric catalysis, so much that it is now comparable to metal catalysis and biocatalysis. Organocatalysis is rationalized and classified by a number of so-called activation modes, based on the formation of a covalent or not-covalent intermediate between the organocatalyst and the organic substrate. Among all the organocatalytic activation modes, enamine and iminium catalysis are widely used for the practical preparation of valuable products and intermediates, both in academic and industrial contexts. In both cases, chiral amines are employed as catalysts. Enamine activation mode is generally employed in the reaction with electrophiles, while nucleophiles require the iminium activation mode. Commonly, in both modes, the reaction occurs through well-organized transitions states. A large variety of partners can react with enamines and iminium ions, due to their sufficient nucleophilicity and electrophilicity, respectively. However, despite the success, organocatalysis still suffers from narrow scopes and applications. Multicatalysis is a possible solution for these drawbacks because the two different catalysts can synergistically activate the substrates, with a simultaneous activation of the two different reaction partners. In particular, in this review we will summarize the reported processes featuring Lewis acid catalysis and organocatalytic activation modes synergically acting and not interfering with each other. We will focus our attention on the description of processes in which good results cannot be achieved independently by organocatalysis or Lewis acid catalysis. In these examples of cooperative dual catalysis, a number of new organic transformations have been developed. The review will focus on the possible strategies, the choice of the Lewis acid and the catalytic cycles involved in the effective reported combination. Additionally, some important key points regarding the rationale for the effective combinations will be also included. π-Activation of organic substrates by Lewis acids, via formation of electrophilic intermediates, and their reaction with enamines will be also discussed in this review.
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Affiliation(s)
- Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy.
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
| | - Simone Potenti
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Francesco Calogero
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
| | - Giacomo Rodeghiero
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
- Cyanagen Srl, Via Stradelli Guelfi 40/C, 40138, Bologna, Italy
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8
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Izzo JA, Poulsen PH, Intrator JA, Jørgensen KA, Vetticatt MJ. Isotope Effects Reveal an Alternative Mechanism for "Iminium-Ion" Catalysis. J Am Chem Soc 2018; 140:8396-8400. [PMID: 29940119 PMCID: PMC6238210 DOI: 10.1021/jacs.8b04856] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A novel mechanism for the epoxidation of enals with hydrogen peroxide catalyzed by diarylprolinol silyl ether supported by experimental 13C kinetic isotope effects (KIEs) and density functional theory calculations is presented. Normal 13C KIEs, measured on both the carbonyl- and β-carbon atoms of the enal, suggest participation of both carbon atoms in the rate-determining step. Calculations show that the widely accepted iminium-ion mechanism does not account for this experimental observation. A syn-SN2' substitution mechanism, which avoids formation of a discrete iminium-ion intermediate, emerges as the most likely mechanism based on agreement between experimental and predicted KIEs.
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Affiliation(s)
- Joseph A. Izzo
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | | | - Jeremy A. Intrator
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | | | - Mathew J. Vetticatt
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
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9
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Azaiez K, Dhahri N, Boubaker T. Reactivity of Nitroalkyl Anions Addition to Substituted Benzylidenecyanoacetates: Electrophilicity Parameters and Free Energy Relationships. INT J CHEM KINET 2017. [DOI: 10.1002/kin.21132] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K. Azaiez
- Laboratoire C.H.P.N.R; Faculté des Sciences de Monastir; Université de Monastir; 5019 Monastir Tunisie
| | - N. Dhahri
- Laboratoire C.H.P.N.R; Faculté des Sciences de Monastir; Université de Monastir; 5019 Monastir Tunisie
| | - T. Boubaker
- Laboratoire C.H.P.N.R; Faculté des Sciences de Monastir; Université de Monastir; 5019 Monastir Tunisie
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10
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Pramanik MMD, Nagode SB, Kant R, Rastogi N. Visible light catalyzed Mannich reaction between tert-amines and silyl diazoenolates. Org Biomol Chem 2017; 15:7369-7373. [DOI: 10.1039/c7ob01756a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The present work documents the α-C–H functionalization of tertiary amines via the visible light catalyzed Mannich reaction with silyl diazoenolates.
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Affiliation(s)
- Mukund M. D. Pramanik
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
| | - Savita B. Nagode
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
| | - Ruchir Kant
- Molecular & Structural Biology Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
| | - Namrata Rastogi
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
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11
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Mayr H. Reactivity scales for quantifying polar organic reactivity: the benzhydrylium methodology. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.055] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Holland MC, Gilmour R. Deconstructing Covalent Organocatalysis. Angew Chem Int Ed Engl 2015; 54:3862-71. [DOI: 10.1002/anie.201409004] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 01/15/2023]
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14
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Holland MC, Metternich JB, Mück-Lichtenfeld C, Gilmour R. Cation–π interactions in iminium ion activation: correlating quadrupole moment & enantioselectivity. Chem Commun (Camb) 2015; 51:5322-5. [DOI: 10.1039/c4cc08520e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A cation–π interaction is operational in the addition of uncharged nucleophiles to iminium salts derived from MacMillan's 1st generation catalyst.
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Affiliation(s)
- M. C. Holland
- Organisch Chemisches Institut
- and Excellence Cluster EXC 1003
- Cells in Motion
- Westfälische Wilhelms-Universität Münster
- Münster
| | - J. B. Metternich
- Organisch Chemisches Institut
- and Excellence Cluster EXC 1003
- Cells in Motion
- Westfälische Wilhelms-Universität Münster
- Münster
| | - C. Mück-Lichtenfeld
- Organisch Chemisches Institut
- and Excellence Cluster EXC 1003
- Cells in Motion
- Westfälische Wilhelms-Universität Münster
- Münster
| | - R. Gilmour
- Organisch Chemisches Institut
- and Excellence Cluster EXC 1003
- Cells in Motion
- Westfälische Wilhelms-Universität Münster
- Münster
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