1
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Inoue T, Morita N, Amijima Y, Sakai R, Hamada S, Nakamura S, Kobayashi Y, Furuta T. Formation of chalcogen-bonding interactions and their role in the trans- trans conformation of thiourea. Org Biomol Chem 2024; 22:5301-5305. [PMID: 38898797 DOI: 10.1039/d4ob00723a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The chalcogen-bonding interactions formed at both sides of the thiocarbonyl group in thiourea were investigated. In particular, the role of these chalcogen-bonding interactions in the trans-trans conformation of thiourea was evaluated via single-crystal X-ray diffraction analysis and DFT calculations. The obtained results indicate that the Se⋯S⋯Se dual chalcogen-bonding interactions play a stronger role in controlling the planar structure than the S⋯S⋯S interactions.
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Affiliation(s)
- Takumi Inoue
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Nami Morita
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Yui Amijima
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Rika Sakai
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Shohei Hamada
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Seikou Nakamura
- Laboratory of Pharmacognosy, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan
| | - Yusuke Kobayashi
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
| | - Takumi Furuta
- Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
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2
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Blechschmidt DR, Mergendahl C, Kass SR. Metallocenium incorporated charge-enhanced thiourea catalysts. Org Biomol Chem 2024; 22:1788-1793. [PMID: 38343361 DOI: 10.1039/d3ob02007j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Several metallocenium derivatives were prepared including N-ferrocenium-N'-phenylthiourea tetrakis-[3,5-bis(trifluoromethyl)phenyl]borate (BArF4, 4a), N-methylferrocenium-N'-phenylthiourea BArF4 (4b) and N-cobaltocenium-N'-phenylthiourea BArF4 (5). These compounds are competent catalysts for the Friedel-Crafts alkylation of indoles with trans-β-nitrostyrenes, and are much more active than their reduced non-charged forms. The iron derivatives are less stable than the cobalt analog and were generated and used in situ whereas the cobalt-containing thiourea was isolated and characterized by X-ray crystallography. All three of these metallocenium salts have Lewis and Brønsted acidic sites which were exploited in tandem to afford charge-activated catalysts.
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Affiliation(s)
- Daniel R Blechschmidt
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA.
| | - Cal Mergendahl
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA.
| | - Steven R Kass
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA.
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3
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Ehrhard A, Gunkel L, Jäger S, Sell AC, Nagata Y, Hunger J. Elucidating Conformation and Hydrogen-Bonding Motifs of Reactive Thiourea Intermediates. ACS Catal 2022; 12:12689-12700. [PMID: 36313523 PMCID: PMC9594049 DOI: 10.1021/acscatal.2c03382] [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: 07/13/2022] [Revised: 09/19/2022] [Indexed: 11/29/2022]
Abstract
Substituted diphenylthioureas (DPTUs) are efficient hydrogen-bonding organo-catalysts, and substitution of DPTUs has been shown to greatly affect catalytic activity. Yet, both the conformation of DPTUs in solution and the conformation and hydrogen-bonded motifs within catalytically active intermediates, pertinent to their mode of activation, have remained elusive. By combining linear and ultrafast vibrational spectroscopy with spectroscopic simulations and calculations, we show that different conformational states of thioureas give rise to distinctively different N-H stretching bands in the infrared spectra. In the absence of hydrogen-bond-accepting substrates, we show that vibrational structure and dynamics are highly sensitive to the substitution of DPTUs with CF3 groups and to the interaction with the solvent environment, allowing for disentangling the different conformational states. In contrast to bare diphenylthiourea (0CF-DPTU), we find the catalytically superior CF3-substituted DPTU (4CF-DPTU) to favor the trans-trans conformation in solution, allowing for donating two hydrogen bonds to the reactive substrate. In the presence of a prototypical substrate, DPTUs in trans-trans conformation hydrogen bond to the substrate's C=O group, as evidenced by a red-shift of the N-H vibration. Yet, our time-resolved infrared experiments indicate that only one N-H group forms a strong hydrogen bond to the carbonyl moiety, while thiourea's second N-H group only weakly interacts with the substrate. Our data indicate that hydrogen-bond exchange between these N-H groups occurs on the timescale of a few picoseconds for 0CF-DPTU and is significantly accelerated upon CF3 substitution. Our results highlight the subtle interplay between conformational equilibria, bonding states, and bonding lifetimes in reactive intermediates in thiourea catalysis, which help rationalize their catalytic activity.
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Affiliation(s)
- Amelie
A. Ehrhard
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lucas Gunkel
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sebastian Jäger
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Arne C. Sell
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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4
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Recchimurzo A, Balzano F, Uccello Barretta G, Gherardi L. Bis-Thiourea Chiral Sensor for the NMR Enantiodiscrimination of N-Acetyl and N-Trifluoroacetyl Amino Acid Derivatives. J Org Chem 2022; 87:11968-11978. [PMID: 36062357 PMCID: PMC9486950 DOI: 10.1021/acs.joc.2c00814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
A C2-symmetrical bis-thiourea chiral solvating agent
(CSA), TFTDA, for NMR spectroscopy has been obtained
by reacting
(1R,2R)-1,2-bis(2-hydroxyphenyl)ethylenediamine
and 3,5-bis(trifluoromethyl)phenyl isothiocyanate. TFTDA shows remarkable propensity to enantiodiscriminate N-trifluoroacetyl (N-TFA) and N-acetyl
(N-Ac) derivatives of amino acids with free carboxyl
functions, with the co-presence of 1,4-diazabicyclo[2.2.2]octane (DABCO)
as the third achiral additive, which is needed for substrate solubilization. TFTDA shows enhanced enantiodiscriminating efficiency in comparison
with the corresponding monomeric counterpart, TFTMA,
pointing out cooperativity between its two symmetrical entities. A
wide range of amino acid derivatives have been efficiently enantiodiscriminated
in CDCl3, with high enantioresolution quotients, which
guarantee high quality in applications devoted to the quantification
of enantiomers. High enantiodiscriminating efficiency is maintained
also in diluted 5 mM conditions or in the presence of sub-stoichiometric
amounts of CSA (0.3 equiv). The role of phenolic hydroxyls in the
DABCO-mediated interaction mechanism between TFTDA and
the two enantiomeric substrates has been pointed out by means of diffusion-ordered
spectroscopy (DOSY) and rotating frame Overhauser effect spectroscopy
(ROESY) experiments. A conformational model for both the CSA and its
diastereomeric solvates formed with the two enantiomers of N-acetyl leucine has also been conceived on the basis of
ROE data in order to give a chiral discrimination rationale.
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Affiliation(s)
- Alessandra Recchimurzo
- Department of Chemistry and Industrial Chemistry, University of Pisa, via Moruzzi 13, 56124 Pisa, Italy
| | - Federica Balzano
- Department of Chemistry and Industrial Chemistry, University of Pisa, via Moruzzi 13, 56124 Pisa, Italy
| | - Gloria Uccello Barretta
- Department of Chemistry and Industrial Chemistry, University of Pisa, via Moruzzi 13, 56124 Pisa, Italy
| | - Luca Gherardi
- Department of Chemistry and Industrial Chemistry, University of Pisa, via Moruzzi 13, 56124 Pisa, Italy
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5
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Scholten K, Merten C. Anion-binding of a chiral tris(2-aminoethyl)amine-based tripodal thiourea: A spectroscopic and computational study. Phys Chem Chem Phys 2022; 24:4042-4050. [DOI: 10.1039/d1cp05688c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thioureas are well-known structural motifs in supramolecular anion recognition. Their conformational preferences are typically characterized by detailed NMR spectroscopy and crystallography, which are often complemented with computational results from geometry...
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6
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Non-Covalent Interactions in Enantioselective Organocatalysis: Theoretical and Mechanistic Studies of Reactions Mediated by Dual H-Bond Donors, Bifunctional Squaramides, Thioureas and Related Catalysts. Catalysts 2021. [DOI: 10.3390/catal11050569] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chiral bifunctional dual H-bond donor catalysts have become one of the pillars of organocatalysis. They include squaramide, thiosquaramide, thiourea, urea, and even selenourea-based catalysts combined with chiral amines, cinchona alkaloids, sulfides, phosphines and more. They can promote several types of reactions affording products in very high yields and excellent stereoselectivities in many cases: conjugate additions, cycloadditions, the aldol and Henry reactions, the Morita–Baylis–Hilman reaction, even cascade reactions, among others. The desire to understand mechanisms and the quest for the origins of stereoselectivity, in attempts to find guidelines for developing more efficient catalysts for new transformations, has promoted many mechanistic and theoretical studies. In this review, we survey the literature published in this area since 2015.
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7
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Sandler I, Chen J, Taylor M, Sharma S, Ho J. Accuracy of DLPNO-CCSD(T): Effect of Basis Set and System Size. J Phys Chem A 2021; 125:1553-1563. [PMID: 33560853 DOI: 10.1021/acs.jpca.0c11270] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The DLPNO-CCSD(T) method is designed to study large molecular systems at significantly reduced cost relative to its canonical counterpart. However, the error in this approach is also size-extensive and relies on cancellation of errors for the calculation of relative energies. This work provides a direct comparison of canonical CCSD(T) and TightPNO DLPNO-CCSD(T) calculations of reaction energies and barriers of a broad range of chemical reactions. The dataset includes acidities, anion binding affinities, enolization, Diels-Alder, nucleophilic substitution, and atom transfer reactions and complements existing theoretical datasets in terms of system size as well as new reaction types (e.g., anion binding affinities and chlorine atom transfer reactions). The performance of DLPNO-CCSD(T) was further examined with respect to systematic variation of basis set and system size and amounts of nonbonded interaction present in the system. The errors in the DLPNO-CCSD(T) were found to be relatively insensitive to the choice of basis set for small systems but increase monotonically with system size. Additionally, calculations of barriers appear to be more challenging than reaction energies with errors exceeding 5 kJ mol-1 for many Diels-Alder reactions. Further tests on three realistic organic reactions reveal the impact of the DLPNO approximation in calculating absolute and relative barriers that are important for predictions such as stereoselectivity.
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Affiliation(s)
- Isolde Sandler
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Junbo Chen
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mackenzie Taylor
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Shaleen Sharma
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Junming Ho
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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8
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Sandler I, Larik FA, Mallo N, Beves JE, Ho J. Anion Binding Affinity: Acidity versus Conformational Effects. J Org Chem 2020; 85:8074-8084. [PMID: 32407087 DOI: 10.1021/acs.joc.0c00888] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
High-level quantum chemical calculations were used to elucidate the gas- and solution-phase conformational equilibria for a series of symmetrically substituted (thio)ureas, (thio)squaramides, and croconamides. Gas-phase calculations predict that the thermodynamic conformer of many of these anion receptors is not the dual-hydrogen-bond-facilitating anti-anti conformer as is commonly assumed. For N,N'-diaryl thiosquaramides and croconamides, the syn-syn conformer is typically the predominant conformer. Solution-phase calculations show that the anti-anti conformer is increasingly stabilized as the polarity of the solvent increases. However, the syn-syn conformer remains the lowest energy conformation for croconamides. These predictions are used to explain the acidity versus chloride binding affinity correlations recently reported for some of these compounds. The chloride binding constants for thioureas and croconamides are significantly lower than expected on the basis of their pKa values, and this may be due in part to the need for these receptors to reorganize into the anti-anti conformer. Experimental NMR nuclear Overhauser effect (NOE) measurements of an asymmetrically substituted squaramide and its thio analogue are consistent with the syn-syn conformation being predominant at 298 K. The conformational equilibria should therefore be an important consideration for the design and development of future anion receptors and organocatalysts.
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Affiliation(s)
- Isolde Sandler
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Fayaz Ali Larik
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Neil Mallo
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Jonathon E Beves
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Junming Ho
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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9
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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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10
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Smajlagic I, Guest M, Durán R, Herrera B, Dudding T. Mechanistic Insight toward Understanding the Role of Charge in Thiourea Organocatalysis. J Org Chem 2020; 85:585-593. [PMID: 31790584 DOI: 10.1021/acs.joc.9b02682] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyranylation and glycosylation are pivotal for accessing a myriad of natural products, pharmaceuticals, and drug candidates. Catalytic approaches for enabling these transformations are of utmost importance and integral to advancing this area of synthesis. In exploring this chemical space, a combined experimental and computational mechanistic study of pyranylation and 2-deoxygalactosylation catalyzed by a cationic thiourea organocatalyst is reported. To this end, a thiourea-cyclopropenium organocatalyst was employed as a model system in combination with an arsenal of mechanistic techniques, including 13C kinetic isotope effect experiments, deuterated labeling studies, variable-temperature 1H NMR spectroscopy, and density functional theory calculations. From these studies, two distinct reaction pathways were identified for this transformation corresponding to either dual hydrogen bond (H-bond) activation or Brønsted acid catalysis. The former involving thiourea orchestrated bifurcated hydrogen bonding proceeded in an asynchronous concerted fashion. In contrast, the latter stepwise mechanism involving Brønsted acid catalysis hinged upon the formation of an oxocarbenium intermediate accompanied by subsequent alcohol addition.
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Affiliation(s)
- Ivor Smajlagic
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , ON L2S 3A1 , Canada
| | - Matt Guest
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , ON L2S 3A1 , Canada
| | - Rocío Durán
- Laboratorio de Química Teórica Computacional (QTC), Departamento de Química-Física, Facultad de Química y de Farmacia , Pontificia Universidad Católica de Chile , Av. Vicuña Mackenna 4860 , Macul, Santiago , Chile
| | - Barbara Herrera
- Laboratorio de Química Teórica Computacional (QTC), Departamento de Química-Física, Facultad de Química y de Farmacia , Pontificia Universidad Católica de Chile , Av. Vicuña Mackenna 4860 , Macul, Santiago , Chile
| | - Travis Dudding
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , ON L2S 3A1 , Canada
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11
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Capobianco A, Meninno S, Lattanzi A. Unravelling the mechanism of the organocatalyzed aminolytic kinetic resolution of α-nitroepoxides: a theoretical study. Catal Sci Technol 2020. [DOI: 10.1039/c9cy01800j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of the aminolytic kinetic resolution of 2-methyl-2-nitro-3-phenyl oxirane with aniline in the presence of Takemoto's catalyst is disclosed by way of DFT calculations.
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Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia “A. Zambelli”
- Università di Salerno
- I-84084 Fisciano
- Italy
| | - Sara Meninno
- Dipartimento di Chimica e Biologia “A. Zambelli”
- Università di Salerno
- I-84084 Fisciano
- Italy
| | - Alessandra Lattanzi
- Dipartimento di Chimica e Biologia “A. Zambelli”
- Università di Salerno
- I-84084 Fisciano
- Italy
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12
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Neuvonen AJ, Noutsias D, Topić F, Rissanen K, Földes T, Pápai I, Pihko PM. Dynamic Refolding of Ion-Pair Catalysts in Response to Different Anions. J Org Chem 2019; 84:15009-15019. [PMID: 31536339 DOI: 10.1021/acs.joc.9b01980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Four distinct folding patterns are identified in two foldamer-type urea-thiourea catalysts bearing a basic dimethylamino unit by a combination of X-ray crystallography, solution NMR studies, and computational studies (DFT). These patterns are characterized by different intramolecular hydrogen bonding schemes that arise largely from different thiourea conformers. The free base forms of the catalysts are characterized by folds where the intramolecular hydrogen bonds between the urea and the thiourea units remain intact. In contrast, the catalytically relevant salt forms of the catalyst, where the catalyst forms an ion pair with the substrate or substrate analogues, appear in two entirely different folding patterns. With larger anions that mimic the dialkyl malonate substrates, the catalysts maintain their native fold both in the solid state and in solution, but with smaller halide anions (fluoride, chloride, and bromide), the catalysts fold around the halide anion (anion receptor fold), and the intramolecular hydrogen bonds are disrupted. Titration of catalyst hexafluoroacetylacetonate salt with tetra-n-butylammonium chloride results in dynamic refolding of the catalyst from the native fold to the anion receptor fold.
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Affiliation(s)
- Antti J Neuvonen
- Department of Chemistry and NanoScience Center , University of Jyväskylä , FI-40014 Jyväskylä , Finland
| | - Dimitris Noutsias
- Department of Chemistry and NanoScience Center , University of Jyväskylä , FI-40014 Jyväskylä , Finland
| | - Filip Topić
- Department of Chemistry and NanoScience Center , University of Jyväskylä , FI-40014 Jyväskylä , Finland
| | - Kari Rissanen
- Department of Chemistry and NanoScience Center , University of Jyväskylä , FI-40014 Jyväskylä , Finland
| | - Tamás Földes
- Institute of Organic Chemistry, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2 , H-1117 Budapest , Hungary
| | - Imre Pápai
- Institute of Organic Chemistry, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2 , H-1117 Budapest , Hungary
| | - Petri M Pihko
- Department of Chemistry and NanoScience Center , University of Jyväskylä , FI-40014 Jyväskylä , Finland
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13
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Prusinowska N, Czapik A, Wojciechowska M, Kwit M. Dynamic optical activity induction in the N-alkyl-N'-trityl ureas and thioureas. Org Biomol Chem 2019; 17:7782-7793. [PMID: 31402354 DOI: 10.1039/c9ob01319a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Considered to be rigid, the urea and thiourea functionalities, often used in material chemistry and in asymmetric organocatalysis, are able to transmit information regarding 3D structure from a permanently chiral inducer part to a dynamically chiral (reporter) part of the molecule. Despite a considerable distance between the inducer and the reporter parts of the molecule, the chirality transfer phenomenon has been demonstrated for a series of secondary N-alkyl-N'-trityl ureas and thioureas. The induction of helicity in a stereodynamic trityl propeller is revealed by rising non-zero Cotton effects in the area of trityl absorption. The information regarding the 3D structure of the inducer is transferred to the reporter part of the system through a set of weak but complementary electrostatic interactions. The presence of two supramolecular motifs in the same molecule, characterized by opposite properties, significantly affected the molecular solid state structure of the thioureas and their abilities to assemble. In the crystalline phase, the model, a chiral N-tert-butyl-thiourea derivative that retains the extended Z,Z conformation of the linker, is prone to form a supramolecular network typical of secondary ureas and thioureas. In contrast, the presence of the hydrophobic trityl group suppresses the thioamide NHS[double bond, length as m-dash]C hydrogen bonds. Therefore, trityl acts as a supramolecular protecting group for thioamide functionality, hampering the formation of hydrogen bonded networks in the solid state.
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Affiliation(s)
- Natalia Prusinowska
- Department of Chemistry Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61 614 Poznań, Poland. and Centre for Advanced Technologies Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61 614 Poznań, Poland.
| | - Agnieszka Czapik
- Department of Chemistry Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61 614 Poznań, Poland. and Centre for Advanced Technologies Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61 614 Poznań, Poland.
| | - Martika Wojciechowska
- Department of Chemistry Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61 614 Poznań, Poland.
| | - Marcin Kwit
- Department of Chemistry Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61 614 Poznań, Poland. and Centre for Advanced Technologies Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61 614 Poznań, Poland.
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14
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Izzo JA, Myshchuk Y, Hirschi JS, Vetticatt MJ. Transition state analysis of an enantioselective Michael addition by a bifunctional thiourea organocatalyst. Org Biomol Chem 2019; 17:3934-3939. [PMID: 30942247 PMCID: PMC6774437 DOI: 10.1039/c9ob00072k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanism of the enantioselective Michael addition of diethyl malonate to trans-β-nitrostyrene catalyzed by a tertiary amine thiourea organocatalyst is explored using experimental 13C kinetic isotope effects and density functional theory calculations. Large primary 13C KIEs on the bond-forming carbon atoms of both reactants suggest that carbon-carbon bond formation is the rate-determining step in the catalytic cycle. This work resolves conflicting mechanistic pictures that have emerged from prior experimental and computational studies.
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Affiliation(s)
- Joseph A Izzo
- Department of Chemistry, Binghamton University, Binghamton, NY 13902, USA.
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15
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Luchini G, Ascough DM, Alegre-Requena JV, Gouverneur V, Paton RS. Data-mining the diaryl(thio)urea conformational landscape: Understanding the contrasting behavior of ureas and thioureas with quantum chemistry. Tetrahedron 2019. [DOI: 10.1016/j.tet.2018.12.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Wåhlander J, Amedjkouh M, Balcells D. A DFT Perspective on Diels–Alder Organocatalysts Based on Substituted Phosphoramides. European J Org Chem 2019. [DOI: 10.1002/ejoc.201800844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jakob Wåhlander
- Department of Chemistry University of Oslo P.O. Box 1033 0315 Blindern, Oslo Norway
| | - Mohamed Amedjkouh
- Department of Chemistry University of Oslo P.O. Box 1033 0315 Blindern, Oslo Norway
| | - David Balcells
- Hylleraas Centre for Quantum Molecular Sciences Department of Chemistry University of Oslo P.O. Box 1033 0315 Blindern, Oslo Norway
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17
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Bradshaw GA, Colgan AC, Allen NP, Pongener I, Boland MB, Ortin Y, McGarrigle EM. Stereoselective organocatalyzed glycosylations - thiouracil, thioureas and monothiophthalimide act as Brønsted acid catalysts at low loadings. Chem Sci 2019; 10:508-514. [PMID: 30713648 PMCID: PMC6334493 DOI: 10.1039/c8sc02788a] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/15/2018] [Indexed: 01/21/2023] Open
Abstract
Thiouracil catalyzes stereoselective glycosylations with galactals in loadings as low as 0.1 mol%. It is proposed that in these glycosylations thiouracil, monothiophthalimide, and the previously reported catalyst, Schreiner's thiourea, do not operate via a double H-bonding mechanism but rather by Brønsted acid/base catalysis. In addition to the synthesis of 2-deoxyglycosides and glycoconjugates, we report the first organocatalytic synthesis of 1,1'-linked trehalose-type sugars.
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Affiliation(s)
- G A Bradshaw
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - A C Colgan
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - N P Allen
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - I Pongener
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - M B Boland
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - Y Ortin
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
| | - E M McGarrigle
- Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland .
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18
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Blyth MT, Coote ML. A pH-Switchable Electrostatic Catalyst for the Diels–Alder Reaction: Progress toward Synthetically Viable Electrostatic Catalysis. J Org Chem 2019; 84:1517-1522. [DOI: 10.1021/acs.joc.8b02940] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Mitchell T. Blyth
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Michelle L. Coote
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
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19
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Yan CX, Wu RZ, Lu K, Yang FL, Yang XS, Wang R, Yang X, Zhou PP, Shao X. Why electrostatically enhanced thiourea is better than Schreiner's thiourea in both catalytic activity and regioselectivity? Org Chem Front 2019. [DOI: 10.1039/c9qo00251k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrostatically enhanced thiourea is more active and efficient than Schreiner's thiourea in the ring-opening aminolysis of styrene oxide with aniline, and the underlying reasons were explored by DFT calculations.
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Affiliation(s)
- Chao-Xian Yan
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Rui-Zhi Wu
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Ka Lu
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Fang-Ling Yang
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Xiao-Shan Yang
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Rui Wang
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Xing Yang
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Pan-Pan Zhou
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Xiangfeng Shao
- State Key Laboratory of Applied Organic Chemistry
- Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
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20
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Smajlagic I, Durán R, Pilkington M, Dudding T. Cyclopropenium Enhanced Thiourea Catalysis. J Org Chem 2018; 83:13973-13980. [PMID: 30352160 DOI: 10.1021/acs.joc.8b02321] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An integral part of modern organocatalysis is the development and application of thiourea catalysts. Here, as part of our program aimed at developing cyclopropenium catalysts, the synthesis of a thiourea-cyclopropenium organocatalyst with both cationic hydrogen-bond donor and electrostatic character is reported. The utility of the this thiourea organocatalyst is showcased in pyranylation reactions employing phenols, primary, secondary, and tertiary alcohols under operationally simple and mild reaction conditions for a broad substrate scope. The addition of benzoic acid as a co-catalyst facilitating cooperative Brønsted acid catalysis was found to be valuable for reactions involving phenols and higher substituted alcohols. Mechanistic investigations, including kinetic and 1H NMR binding studies in conjunction with density function theory calculations, are described that collectively support a Brønsted acid mode of catalysis.
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Affiliation(s)
- Ivor Smajlagic
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario L2S 3A1 , Canada
| | - Rocio Durán
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario L2S 3A1 , Canada
| | - Melanie Pilkington
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario L2S 3A1 , Canada
| | - Travis Dudding
- Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario L2S 3A1 , Canada
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21
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Heshmat M. Unraveling the Origin of Solvent Induced Enantioselectivity in the Henry Reaction with Cinchona Thiourea as Catalyst. J Phys Chem A 2018; 122:7974-7982. [PMID: 30230831 DOI: 10.1021/acs.jpca.8b04589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, we report an energy decomposition and electronic structure analysis using DFT calculations for the C-C coupling step in the Henry reaction with cinchona thiourea as catalyst and DMF solvent to unravel the origin of enantioselectivity. We found that the conformation of flexible thiourea moiety is affected by the solvent, and in the preferred conformation of thiourea in strong Lewis basic DMF solvent, the N-H sites are in the opposite direction, i.e., in trans conformation. Hence, the thiourea moiety acts via single hydrogen bonding with substrates. The conformation of the substrates with respect to the forming C-C bond plays critical role to increase orbital interaction between two substrates and enhances hydrogen bond strength between substrates and catalyst, which in turn stabilizes the positive charge developing on the catalyst at the transition state for one of the enantiomers ( S). Thus, the enantioselectivity has electronic structure origin. The stronger H-bond formation in the S enantiomer has been confirmed by the calculated IR spectra and is in agreement with thus far experimental and computational results.
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Affiliation(s)
- Mojgan Heshmat
- Department of Organic Chemistry , Stockholm University , Stockholm , 10691 , Sweden.,Theoretical Chemistry , Vrije Universiteit Amsterdam , De Boelelaan 1083 , 1081 HV Amsterdam , The Netherlands
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22
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Comparing quantitative prediction methods for the discovery of small-molecule chiral catalysts. Nat Rev Chem 2018. [DOI: 10.1038/s41570-018-0040-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Fan Y, Payne C, Kass SR. Quantification of Catalytic Activity for Electrostatically Enhanced Thioureas via Reaction Kinetics and UV-vis Spectroscopic Measurement. J Org Chem 2018; 83:10855-10863. [PMID: 30021436 DOI: 10.1021/acs.joc.8b01552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Charged thiourea derivatives containing one and two methylated or octylated pyridinium ion centers and a tetraarylborate or triflate counteranion are reported. These novel catalysts are much more active in the Friedel-Crafts reactions of trans-β-nitroalkenes with N-methylindoles than the privileged N, N'-bis(3,5-bis(trifluoromethyl)phenyl)thiourea (i.e., Schreiner's thiourea) by up to 2-3 orders of magnitude. A previously reported UV-vis spectroscopic method by Kozlowski et al. was exploited to rationalize their reactivity order along with noncharged analogues. These results offer a new design strategy for organocatalysts by introducing positively charged centers without adding additional N-H, O-H, or S-H hydrogen bond donor sites.
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Affiliation(s)
- Yang Fan
- Department of Chemistry , University of Minnesota , 207 Pleasant Street, SE , Minneapolis , Minnesota 55455 , United States
| | - Curtis Payne
- Department of Chemistry , University of Minnesota , 207 Pleasant Street, SE , Minneapolis , Minnesota 55455 , United States
| | - Steven R Kass
- Department of Chemistry , University of Minnesota , 207 Pleasant Street, SE , Minneapolis , Minnesota 55455 , United States
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