1
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Rufino VC, Pliego JR. Bifunctional iminophosphorane organocatalyst with additional hydrogen bonding: Calculations predict enhanced catalytic performance in a michael addition reaction. J Mol Graph Model 2024; 129:108760. [PMID: 38513601 DOI: 10.1016/j.jmgm.2024.108760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/29/2024] [Accepted: 03/11/2024] [Indexed: 03/23/2024]
Abstract
A new iminophosphorane-thiourea superbase was rationally designed and investigated as an organocatalyst for the enantioselective Michael addition reaction of nitromethane to 4-phenylbut-3-en-2-one. Starting from an iminophosphorane-thiourea organocatalyst structure already known, we have used theoretical calculations to determine the structures of transition states involved in the carbon-carbon bond formation step and carried out structural modifications to accelerate the reaction rate and to increase the enantioselectivity. The effective structural modification was adding a rigid hydroxyl group able to make an additional hydrogen bond to the transition state, producing a substantial decrease of the ΔG‡ by 7 kcal mol-1. The enantiomeric excess is predicted to be above of 97% using the reliable M06-2X and ωB97M - V functionals. The determination of the complete reaction mechanism and free energy profile was followed by a detailed microkinetic analysis. The present study points out a new direction for structural modifications on this kind of organocatalyst.
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Affiliation(s)
- Virginia C Rufino
- Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João del-Rei, MG, Brazil
| | - Josefredo R Pliego
- Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João del-Rei, MG, Brazil.
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2
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Kitzinger KM, Giordano MT, de Jesús Cruz P, Johnson JS. Diastereoselective (3 + 3)-Annulations of Trisubstituted Michael Acceptors for Access to Polyfunctional Cyclohexanones. J Org Chem 2024; 89:5878-5882. [PMID: 38501591 PMCID: PMC11181156 DOI: 10.1021/acs.joc.4c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Michael-aldol domino reactions are powerful tools for rapidly assembling carbocyclic scaffolds. We herein disclose a base-catalyzed Michael-aldol domino reaction of trisubstituted Michael acceptors with β-keto ester nucleophiles. The cyclohexanone products are obtained in excellent diastereoselectivity (up to >20:1 dr) and good yields (up to 84%). An attractive practical consideration is that pure products are isolated directly via filtration of the unpurified reaction mixtures. Further functionalization of the cyclohexanones is achieved without perturbation of stereocenters installed through the preceding annulation.
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Affiliation(s)
- Katelyn M Kitzinger
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Mitchell T Giordano
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Pedro de Jesús Cruz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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3
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Poh CYX, Rozsar D, Yang J, Christensen KE, Dixon DJ. Bifunctional Iminophosphorane Catalyzed Amide Enolization for Enantioselective Cyclohexadienone Desymmetrization. Angew Chem Int Ed Engl 2023:e202315401. [PMID: 38055190 DOI: 10.1002/anie.202315401] [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: 10/12/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023]
Abstract
The organocatalytic enolization of 2-arylacetamides, followed by an enantioselective intramolecular conjugate addition to tethered 2,5-cyclohexadienones, yielding 3D fused N-heterocycles, is described. The transformation represents the first strong activating group-free activation of carboxamides via α-C-H deprotonation in a metal-free, catalytic, and enantioselective reaction, and is achieved by employing a bifunctional iminophosphorane (BIMP) superbase.
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Affiliation(s)
- Charmaine Y X Poh
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Daniel Rozsar
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Jinchao Yang
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Kirsten E Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Darren J Dixon
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
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4
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Giordano MT, Kitzinger KM, de Jesús Cruz P, Liu S, Johnson JS. Catalytic, Asymmetric Michael-Aldol Annulations via a Stereodivergent/Stereoconvergent Path Operating under Curtin-Hammett Control. J Am Chem Soc 2023; 145:12370-12376. [PMID: 37216269 PMCID: PMC10360212 DOI: 10.1021/jacs.3c03373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A bifunctional iminophosphorane (BIMP)-catalyzed method for the synthesis of densely functionalized cyclohexanols establishes five contiguous stereocenters (diastereoselection up to >20:1, enantioselectivity up to >99:1) in a Michael/aldol domino reaction between trisubstituted electrophilic alkenes and γ-nitroketones. Mechanistic studies suggest a scenario in which stereoconvergency is achieved by kinetically controlled cyclization after the initial diastereodivergent Michael addition. Diastereoconvergency during cyclization is shown to result from Curtin-Hammett kinetics, a finding that contrasts the crystallization-driven stereoconvergency previously reported in similar systems. Despite the change in the stereocontrol mechanism, the operational attributes remain attractive, with the crystalline products typically isolated in analytically pure form upon filtration of the reaction mixture.
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Affiliation(s)
- Mitchell T Giordano
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Katelyn M Kitzinger
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Pedro de Jesús Cruz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Shubin Liu
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
- Research Computing Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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5
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Rozsar D, Farley AJM, McLauchlan I, Shennan BDA, Yamazaki K, Dixon DJ. Bifunctional Iminophosphorane-Catalyzed Enantioselective Nitroalkane Addition to Unactivated α,β-Unsaturated Esters. Angew Chem Int Ed Engl 2023; 62:e202303391. [PMID: 36929179 PMCID: PMC10946890 DOI: 10.1002/anie.202303391] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/18/2023]
Abstract
Herein we describe the enantioselective intermolecular conjugate addition of nitroalkanes to unactivated α,β-unsaturated esters, catalyzed by a bifunctional iminophosphorane (BIMP) superbase. The transformation provides the most direct access to pharmaceutically relevant enantioenriched γ-nitroesters, utilizing feedstock chemicals, with unprecedented selectivity. The methodology exhibits a broad substrate scope, including β-(fluoro)alkyl, aryl and heteroaryl substituted electrophiles, and was successfully applied on a gram scale with reduced catalyst loading, and, additionally, catalyst recovery was carried out. The formal synthesis of a range of drug molecules, and an enantioselective synthesis of (S)-rolipram were achieved. Additionally, computational studies revealed key reaction intermediates and transition state structures, and provided rationale for high enantioselectivities, in good agreement with experimental results.
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Affiliation(s)
- Daniel Rozsar
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOX1 3TAOxfordUK
| | - Alistair J. M. Farley
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOX1 3TAOxfordUK
| | - Iain McLauchlan
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOX1 3TAOxfordUK
| | | | - Ken Yamazaki
- Division of Applied ChemistryOkayama University700-8530TsushimanakaOkayamaJapan
| | - Darren J. Dixon
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOX1 3TAOxfordUK
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6
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Rozsar D, Formica M, Yamazaki K, Hamlin TA, Dixon DJ. Bifunctional Iminophosphorane-Catalyzed Enantioselective Sulfa-Michael Addition to Unactivated α,β-Unsaturated Amides. J Am Chem Soc 2022; 144:1006-1015. [PMID: 34990142 PMCID: PMC8793149 DOI: 10.1021/jacs.1c11898] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
The
first metal-free catalytic intermolecular enantioselective
Michael addition to unactivated α,β-unsaturated amides
is described. Consistently high enantiomeric excesses and yields were
obtained over a wide range of alkyl thiol pronucleophiles and electrophiles
under mild reaction conditions, enabled by a novel squaramide-based
bifunctional iminophosphorane catalyst. Low catalyst loadings (2.0
mol %) were achieved on a decagram scale, demonstrating the scalability
of the reaction. Computational analysis revealed the origin of the
high enantiofacial selectivity via analysis of relevant transition
structures and provided substantial support for specific noncovalent
activation of the carbonyl group of the α,β-unsaturated
amide by the catalyst.
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Affiliation(s)
- Daniel Rozsar
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Michele Formica
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Ken Yamazaki
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom.,Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Darren J Dixon
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
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7
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Tukhtaev HB, Bezzubov SI, Tarasenko EA, Melnikov MY, Ivanov KL, Budynina EM. Time‐Dependent Diastereodivergent Michael Addition Enabled by Phosphazenes Acting as Catalysts and Reactants. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hamidulla B. Tukhtaev
- Lomonosov Moscow State University Department of Chemistry Leninskie gory 1–3 Moscow 119991 Russia
| | - Stanislav I. Bezzubov
- Kurnakov Institute of General and Inorganic Chemistry Russian Academy of Sciences Leninskiy pr. 31 Moscow 119991 Russia
| | - Elena A. Tarasenko
- Lomonosov Moscow State University Department of Chemistry Leninskie gory 1–3 Moscow 119991 Russia
| | - Mikhail Ya. Melnikov
- Lomonosov Moscow State University Department of Chemistry Leninskie gory 1–3 Moscow 119991 Russia
| | - Konstantin L. Ivanov
- Lomonosov Moscow State University Department of Chemistry Leninskie gory 1–3 Moscow 119991 Russia
| | - Ekaterina M. Budynina
- Lomonosov Moscow State University Department of Chemistry Leninskie gory 1–3 Moscow 119991 Russia
- Lebedev Physical Institute Russian Academy of Sciences Leninskiy pr. 53 Moscow 119991 Russia
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8
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Puglisi A, Rossi S. Stereoselective organocatalysis and flow chemistry. PHYSICAL SCIENCES REVIEWS 2021. [DOI: 10.1515/psr-2018-0099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Organic synthesis has traditionally been performed in batch. Continuous-flow chemistry was recently rediscovered as an enabling technology to be applied to the synthesis of organic molecules. Organocatalysis is a well-established methodology, especially for the preparation of enantioenriched compounds. In this chapter we discuss the use of chiral organocatalysts in continuous flow. After the classification of the different types of catalytic reactors, in Section 2, each class will be discussed with the most recent and significant examples reported in the literature. In Section 3 we discuss homogeneous stereoselective reactions in flow, with a look at the stereoselective organophotoredox transformations in flow. This research topic is emerging as one of the most powerful method to prepare enantioenriched products with structures that would otherwise be challenging to make. Section 4 describes the use of supported organocatalysts in flow chemistry. Part of the discussion will be devoted to the choice of the support. Examples of packed-bed, monolithic and inner-wall functionalized reactors will be introduced and discussed. We hope to give an overview of the potentialities of the combination of (supported) chiral organocatalysts and flow chemistry.
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Affiliation(s)
- Alessandra Puglisi
- Dipartimento di Chimica , Università degli Studi di Milano , via Golgi 19 , Milano , 20133 Italy
| | - Sergio Rossi
- Dipartimento di Chimica , Università degli Studi di Milano , via Golgi 19 , Milano , 20133 Italy
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9
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Formica M, Rozsar D, Su G, Farley AJM, Dixon DJ. Bifunctional Iminophosphorane Superbase Catalysis: Applications in Organic Synthesis. Acc Chem Res 2020; 53:2235-2247. [PMID: 32886474 DOI: 10.1021/acs.accounts.0c00369] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To improve the field of catalysis, there is a substantial and growing need for novel high-performance catalysts providing new reactivity. To date, however, the set of reactions that can be reliably performed to prepare chiral compounds in largely one enantiomeric form using chiral catalysts still represents a small fraction of the toolkit of known transformations. In this context, chiral Brønsted bases have played an expanding role in catalyzing enantioselective reactions between various carbon- and heteroatom-centered acids and a host of electrophilic reagents. This Account describes our recent efforts developing and applying a new family of chiral Brønsted bases incorporating an H-bond donor moiety and a strongly basic iminophosphorane, which we have named BIMPs (Bifunctional IMinoPhosphoranes), as efficient catalysts for reactions currently out of reach of more widespread tertiary amine centered bifunctional catalysts. The iminophosphorane Brønsted base is easily generated by the Staudinger reaction of a chiral organoazide and commercially available phosphine, which allows easy modification of the catalyst structure and fine-tuning of the iminophosphorane pKBH+. We have demonstrated that BIMP catalysts can efficiently promote the enantioselective addition of nitromethane to low reactivity N-diphenylphosphinoyl (DPP)-protected imines of ketones (ketimines) to access valuable chiral diamine and α-quaternary amino acid building blocks, and later extended this methodology to phosphite nucleophiles. Subsequently, the reaction scope was expanded to include the Michael addition of high pKa alkyl thiols to α-substituted acrylate esters, β-substituted α,β-unsaturated esters, and alkenyl benzimidazoles as well as the challenging direct aldol addition of aryl ketones to α-fluorinated ketones. Finally, BIMP catalysts were shown to be used in key steps in the synthesis of complex alkaloid natural products (-)-nakadomarin A and (-)-himalensine A, as well as in polymer synthesis. In most cases, the predictable nature of the BIMP promoted reactions was demonstrated by multigram scale-up while employing low catalyst loadings (down to 0.05 mol%). Furthermore, it was shown that BIMP catalysts can be easily immobilized onto a solid support in one-step for increased catalyst recycling and flow chemistry applications. Alongside our own work, this Account also includes elegant work by Johnson and co-workers utilizing the BIMP catalyst system, when alternative catalysts proved suboptimal.
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Affiliation(s)
- Michele Formica
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Daniel Rozsar
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Guanglong Su
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Alistair J. M. Farley
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Darren J. Dixon
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
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10
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Saadat K, Shiri A, Kovačević B. Step Forward to Stronger Neutral Organic Superbases: Fused Troponimines. J Org Chem 2020; 85:11375-11381. [DOI: 10.1021/acs.joc.0c01466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kayvan Saadat
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
| | - Ali Shiri
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
| | - Borislav Kovačević
- Group for Computational Life Science, Division of Chemistry, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia
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11
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Affiliation(s)
- Romain Morodo
- Center for Integrated Technology and Organic Synthesis MolSys Research Unit University of Liège B‐4000 Liège (Sart Tilman) Belgium
| | - Pauline Bianchi
- Center for Integrated Technology and Organic Synthesis MolSys Research Unit University of Liège B‐4000 Liège (Sart Tilman) Belgium
| | - Jean‐Christophe M. Monbaliu
- Center for Integrated Technology and Organic Synthesis MolSys Research Unit University of Liège B‐4000 Liège (Sart Tilman) Belgium
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12
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Pliego JR. Theoretical free energy profile and benchmarking of functionals for amino-thiourea organocatalyzed nitro-Michael addition reaction. Phys Chem Chem Phys 2020; 22:11529-11536. [PMID: 32393952 DOI: 10.1039/d0cp00481b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Amino-thiourea organocatalysis is an important catalytic process for enantioselective conjugate addition reactions. The interaction of the reactants with the catalyst has a substantial effect of dispersion forces and is a challenge for a reliable description when applying density functional theory. In this report, the classical addition of acetylacetone to β-nitro-styrene catalyzed by Takemoto's catalyst in toluene was studied using the PBE functional for geometry optimization and the DLPNO-CCSD(T) benchmark method for single point energy. The complete free energy profile calculated for the reaction was able to explain all experimental observations, including the fact that the carbon-carbon bond formation step is rate-determining. The overall barrier was calculated to be 22.8 kcal mol-1 (experimental value approximately 20 kcal mol-1), and the enantiomeric excess was calculated to be 88% (experimental value in the range of 84 to 92%). Some functionals were tested for single point energy. The hybrid B3LYP presented a high mean absolute deviation (MAD) from the DLPNO-CCSD(T) benchmark method by approximately 20 kcal mol-1. The inclusion of empirical dispersion correction in the B3LYP method decreased the MAD to 6 kcal mol-1. Even the double-hybrid mPW2-PLYP and B2GP-PLYP methods had MAD values of approximately 5 kcal mol-1. The inclusion of the dispersion correction decreased the MAD to 3.6 kcal mol-1. M06-2X and ωB97X-D3 were the most accurate among the tested functionals, with MADs of 2.5 kcal mol-1 and 1.8 kcal mol-1, respectively. Additivity approximation of the correlation energy was also tested and presented a MAD of only 0.6 kcal mol-1.
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Affiliation(s)
- Josefredo R Pliego
- Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João del-Rei, MG, Brazil.
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13
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Thomson CJ, Barber DM, Dixon DJ. Catalytic Enantioselective Direct Aldol Addition of Aryl Ketones to α‐Fluorinated Ketones. Angew Chem Int Ed Engl 2020; 59:5359-5364. [DOI: 10.1002/anie.201916129] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Indexed: 01/17/2023]
Affiliation(s)
- Connor J. Thomson
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford Mansfield Road Oxford OX1 3TA UK
| | - David M. Barber
- Research & DevelopmentWeed Control ChemistryBayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - Darren J. Dixon
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford Mansfield Road Oxford OX1 3TA UK
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14
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Thomson CJ, Barber DM, Dixon DJ. Catalytic Enantioselective Direct Aldol Addition of Aryl Ketones to α‐Fluorinated Ketones. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Connor J. Thomson
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford Mansfield Road Oxford OX1 3TA UK
| | - David M. Barber
- Research & DevelopmentWeed Control ChemistryBayer AG, Crop Science Division Industriepark Höchst 65926 Frankfurt am Main Germany
| | - Darren J. Dixon
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford Mansfield Road Oxford OX1 3TA UK
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15
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Domino Michael/aza-Wittig reaction in the diastereoselective construction of spiro[azepane-4,3′-oxindoles]. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.06.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Valadbeigi Y, Vianello R. A density functional theory study on the superacidity of sulfuric, fluorosulfuric, and triflic acid derivatives with two cyclopentadiene rings: ion pairs formation in the gas phase. J PHYS ORG CHEM 2019. [DOI: 10.1002/poc.3995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Younes Valadbeigi
- Department of Chemistry, Faculty of ScienceImam Khomeini International University Qazvin Iran
| | - Robert Vianello
- Computational Organic Chemistry and Biochemistry Group, Division of Organic Chemistry and BiochemistryRuđer Bošković Institute Zagreb Croatia
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17
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Ivanov KL, Melnikov MY, Budynina EM. Phosphazenomalonates as Catalysts and Reactants in (4+3) Annulation to Acrolein. Org Lett 2019; 21:4464-4468. [PMID: 31184158 DOI: 10.1021/acs.orglett.9b01292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The concept of combining a catalyst and an activated center in one molecule was implemented in Michael donors functionalized with phosphazene units. First, the phosphazene group catalyzes Michael addition and then acts as a reactant in an intramolecular aza-Wittig reaction. The viability of this strategy was demonstrated by our development of a one-pot method for azepane core construction starting from functionalized azides, triphenylphosphine and acrolein.
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Affiliation(s)
- Konstantin L Ivanov
- Department of Chemistry , Lomonosov Moscow State University , Leninskie gory 1-3 , Moscow 119991 , Russia
| | - Mikhail Ya Melnikov
- Department of Chemistry , Lomonosov Moscow State University , Leninskie gory 1-3 , Moscow 119991 , Russia
| | - Ekaterina M Budynina
- Department of Chemistry , Lomonosov Moscow State University , Leninskie gory 1-3 , Moscow 119991 , Russia
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