51
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Jeppesen A, Nielsen BE, Larsen D, Akselsen OM, Sølling TI, Brock-Nannestad T, Pittelkow M. Croconamides: a new dual hydrogen bond donating motif for anion recognition and organocatalysis. Org Biomol Chem 2018; 15:2784-2790. [PMID: 28272644 DOI: 10.1039/c7ob00441a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We introduce bis-aryl croconamides as a new member in the family of dual hydrogen bonding anion receptors. In this study a series of croconamides are synthesised, and the selectivity for anion binding is investigated (Cl- > Br- > I- in CH2Cl2). The croconamides exhibit different structures in the crystal phase depending on the substituents on the aromatic rings, and furthermore, the crystal structure revealed the presence of tautomers. DFT calculations elucidated the complex structures formed upon addition of anion to the croconamides, confirming the order of association constants towards the halogen anions. The use of croconamides as organocatalysts in a proof-of-concept study is demonstrated in the formation of THP ethers. In addition to this, construction of a Hammet plot further elucidates the mechanism in action on formation of THP ethers.
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Affiliation(s)
- Anne Jeppesen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Bjarne E Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Dennis Larsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Olivia M Akselsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Theis I Sølling
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Theis Brock-Nannestad
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Michael Pittelkow
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
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52
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Wolf FF, Neudörfl JM, Goldfuss B. Hydrogen-bonding cyclodiphosphazanes: superior effects of 3,5-(CF3)2-substitution in anion-recognition and counter-ion catalysis. NEW J CHEM 2018. [DOI: 10.1039/c7nj04660j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Syntheses, X-ray characterization and employment of new cyclodiphosph(v)azane hydrogen-bonding catalysts in experimental and computational anion recognition and the N-acyl-Mannich reaction.
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Affiliation(s)
- Florian F. Wolf
- Institut für Organische Chemie
- Universität zu Köln
- 50939 Köln
- Germany
| | - Jörg-M. Neudörfl
- Institut für Organische Chemie
- Universität zu Köln
- 50939 Köln
- Germany
| | - Bernd Goldfuss
- Institut für Organische Chemie
- Universität zu Köln
- 50939 Köln
- Germany
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53
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Zwicker VE, Yuen KKY, Smith DG, Ho J, Qin L, Turner P, Jolliffe KA. Deltamides and Croconamides: Expanding the Range of Dual H‐bond Donors for Selective Anion Recognition. Chemistry 2017; 24:1140-1150. [DOI: 10.1002/chem.201704388] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - David G. Smith
- School of Chemistry The University of Sydney NSW 2006 Australia
| | - Junming Ho
- School of Chemistry University of New South Wales NSW 2052 Australia
| | - Lei Qin
- School of Chemistry The University of Sydney NSW 2006 Australia
| | - Peter Turner
- School of Chemistry The University of Sydney NSW 2006 Australia
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54
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Kroc MA, Prajapati A, Wink DJ, Anderson LL. Cascade Synthesis of 3-Functionalized Indoles from Nitrones and Their Conversion to Cycloheptanone-Fused Indoles. J Org Chem 2017; 83:1085-1094. [DOI: 10.1021/acs.joc.7b02638] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Michelle A. Kroc
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Ami Prajapati
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Donald J. Wink
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Laura L. Anderson
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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55
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Wang P, Gao Y, Zhao Y, Liu W, Wang Y. Unveiling Mechanism of a Quinine-Squaramide Catalyzed Enantioselective Aza-Friedel–Crafts Reaction between Cyclic Trifluoromethyl Ketimine and Naphthol: A DFT Study. J Org Chem 2017; 82:13109-13114. [DOI: 10.1021/acs.joc.7b02168] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ping Wang
- College of Chemistry, Chemical Engineering
and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Yun Gao
- College of Chemistry, Chemical Engineering
and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Yang Zhao
- College of Chemistry, Chemical Engineering
and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Wei Liu
- College of Chemistry, Chemical Engineering
and Materials Science, Soochow University, Suzhou 215123, PR China
| | - Yong Wang
- College of Chemistry, Chemical Engineering
and Materials Science, Soochow University, Suzhou 215123, PR China
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56
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Banik SM, Levina A, Hyde AM, Jacobsen EN. Lewis acid enhancement by hydrogen-bond donors for asymmetric catalysis. Science 2017; 358:761-764. [PMID: 29123063 PMCID: PMC5728151 DOI: 10.1126/science.aao5894] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/12/2017] [Indexed: 01/10/2023]
Abstract
Small-molecule dual hydrogen-bond (H-bond) donors such as ureas, thioureas, squaramides, and guanidinium ions enjoy widespread use as effective catalysts for promoting a variety of enantioselective reactions. However, these catalysts are only weakly acidic and therefore require highly reactive electrophilic substrates to be effective. We introduce here a mode of catalytic activity with chiral H-bond donors that enables enantioselective reactions of relatively unreactive electrophiles. Squaramides are shown to interact with silyl triflates by binding the triflate counterion to form a stable, yet highly Lewis acidic, complex. The silyl triflate-chiral squaramide combination promotes the generation of oxocarbenium intermediates from acetal substrates at low temperatures. Enantioselectivity in nucleophile additions to the cationic intermediates is then controlled through a network of noncovalent interactions between the squaramide catalyst and the oxocarbenium triflate.
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Affiliation(s)
- Steven M Banik
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anna Levina
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Alan M Hyde
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Eric N Jacobsen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
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57
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Kaya U, Chauhan P, Mahajan S, Deckers K, Valkonen A, Rissanen K, Enders D. Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709224] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Uğur Kaya
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Suruchi Mahajan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Kristina Deckers
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Arto Valkonen
- Department of Chemistry, Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Kari Rissanen
- Department of Chemistry, Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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58
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Kaya U, Chauhan P, Mahajan S, Deckers K, Valkonen A, Rissanen K, Enders D. Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines. Angew Chem Int Ed Engl 2017; 56:15358-15362. [DOI: 10.1002/anie.201709224] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Uğur Kaya
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Suruchi Mahajan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Kristina Deckers
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Arto Valkonen
- Department of Chemistry, Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Kari Rissanen
- Department of Chemistry, Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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59
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Ho J, Zwicker VE, Yuen KKY, Jolliffe KA. Quantum Chemical Prediction of Equilibrium Acidities of Ureas, Deltamides, Squaramides, and Croconamides. J Org Chem 2017; 82:10732-10736. [DOI: 10.1021/acs.joc.7b02083] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Junming Ho
- School
of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
- School
of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Vincent E. Zwicker
- School
of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Karen K. Y. Yuen
- School
of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
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60
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Li Z, Li X, Cheng JP. An Acidity Scale of Triazolium-Based NHC Precursors in DMSO. J Org Chem 2017; 82:9675-9681. [DOI: 10.1021/acs.joc.7b01755] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhen Li
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xin Li
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Jin-Pei Cheng
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
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61
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Li Y, Yang GH, Shen YY, Xue XS, Li X, Cheng JP. N-tert-Butyl Sulfinyl Squaramide Receptors for Anion Recognition through Assisted tert-Butyl C–H Hydrogen Bonding. J Org Chem 2017; 82:8662-8667. [DOI: 10.1021/acs.joc.7b01634] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yao Li
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Guo-Hui Yang
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Ye-Ye Shen
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xiao-Song Xue
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xin Li
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Jin-Pei Cheng
- State Key Laboratory of Elemento-Organic
Chemistry, College of Chemistry, Collaborative Innovation Center of
Chemical Science and Engineering, Nankai University, Tianjin 300071, China
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62
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Sivamuthuraman K, Kumarswamyreddy N, Kesavan V. Diastereo- and Enantioselective Synthesis of 2,2-Disubstituted Benzofuran-3-one Bearing Adjacent Quaternary and Tertiary Stereocenters. J Org Chem 2017; 82:10812-10822. [DOI: 10.1021/acs.joc.7b01105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Koilpitchai Sivamuthuraman
- Chemical Biology Laboratory,
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai-600036, India
| | - Nandarapu Kumarswamyreddy
- Chemical Biology Laboratory,
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai-600036, India
| | - Venkitasamy Kesavan
- Chemical Biology Laboratory,
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai-600036, India
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63
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Squaraine dyes: The hierarchical synthesis and its application in optical detection. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2017. [DOI: 10.1016/j.jphotochemrev.2017.03.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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64
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López C, Ximenis M, Orvay F, Rotger C, Costa A. Supramolecular Hydrogels Based on Minimalist Amphiphilic Squaramide-Squaramates for Controlled Release of Zwitterionic Biomolecules. Chemistry 2017; 23:7590-7594. [DOI: 10.1002/chem.201701029] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 01/17/2023]
Affiliation(s)
- Carlos López
- Departament de Química, Facultad de Ciències; Universitat de les Illes Balears; Ctra. Valldemossa, Km. 7.5 Palma 07122 Spain
| | - Marta Ximenis
- Departament de Química, Facultad de Ciències; Universitat de les Illes Balears; Ctra. Valldemossa, Km. 7.5 Palma 07122 Spain
| | - Francisca Orvay
- Departament de Química, Facultad de Ciències; Universitat de les Illes Balears; Ctra. Valldemossa, Km. 7.5 Palma 07122 Spain
| | - Carmen Rotger
- Departament de Química, Facultad de Ciències; Universitat de les Illes Balears; Ctra. Valldemossa, Km. 7.5 Palma 07122 Spain
| | - Antonio Costa
- Departament de Química, Facultad de Ciències; Universitat de les Illes Balears; Ctra. Valldemossa, Km. 7.5 Palma 07122 Spain
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65
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Rostami A, Sadeh E, Ahmadi S. Exploration of tertiary aminosquaramide bifunctional organocatalyst in controlled/living ring-opening polymerization of l-lactide. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/pola.28641] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ali Rostami
- Department of Polymer and Material Chemistry; Shahid Beheshti University; Tehran 19839-4716 I. R. Iran
| | - Elahe Sadeh
- Department of Polymer and Material Chemistry; Shahid Beheshti University; Tehran 19839-4716 I. R. Iran
| | - Shaghayegh Ahmadi
- Department of Polymer and Material Chemistry; Shahid Beheshti University; Tehran 19839-4716 I. R. Iran
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66
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Rombola M, Sumaria CS, Montgomery TD, Rawal VH. Development of Chiral, Bifunctional Thiosquaramides: Enantioselective Michael Additions of Barbituric Acids to Nitroalkenes. J Am Chem Soc 2017; 139:5297-5300. [PMID: 28375610 DOI: 10.1021/jacs.7b01115] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a general method for the synthesis of chiral thiosquaramides, a class of bifunctional catalysts not previously described in the literature. Thiosquaramides are found to be more acidic and significantly more soluble in nonpolar solvents than their oxosquaramide counterparts, and they are excellent catalysts for the unreported, enantioselective conjugate addition reaction of the barbituric acid pharmacaphore to nitroalkenes, delivering the chiral barbiturate derivatives in high yields and high enantioselectivities, even with catalyst loadings as low as 0.05 mol%.
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Affiliation(s)
- Michael Rombola
- Department of Chemistry, University of Chicago , 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Chintan S Sumaria
- Department of Chemistry, University of Chicago , 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Thomas D Montgomery
- Department of Chemistry, University of Chicago , 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Viresh H Rawal
- Department of Chemistry, University of Chicago , 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
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67
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Grayson MN. Mechanism and Origins of Stereoselectivity in the Cinchona Thiourea- and Squaramide-Catalyzed Asymmetric Michael Addition of Nitroalkanes to Enones. J Org Chem 2017; 82:4396-4401. [PMID: 28319377 DOI: 10.1021/acs.joc.7b00521] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report density functional theory calculations that examine the mechanism and origins of stereoselectivity of Soós' landmark discovery from 2005 that cinchona thioureas catalyze the asymmetric Michael addition of nitroalkanes to enones. We show that the electrophile is activated by the catalyst's protonated amine and that the nucleophile binds to the thiourea moiety by hydrogen bonding. These results lead to the correction of published mechanistic work which did not consider this activation mode. We have also investigated the corresponding cinchona squaramide-catalyzed reaction and found that it proceeds by the same mechanism despite the differences in the geometry of the two catalysts' hydrogen-bond-donating groups, which demonstrates the generality of this mechanistic model.
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Affiliation(s)
- Matthew N Grayson
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom
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68
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Guo J, Wong MW. Cinchona Alkaloid-Squaramide Catalyzed Sulfa-Michael Addition Reaction: Mode of Bifunctional Activation and Origin of Stereoinduction. J Org Chem 2017; 82:4362-4368. [DOI: 10.1021/acs.joc.7b00388] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Jinlong Guo
- NUS
Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Ming Wah Wong
- NUS
Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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69
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Yang C, Wang J, Liu Y, Ni X, Li X, Cheng J. Study on the Catalytic Behavior of Bifunctional Hydrogen‐Bonding Catalysts Guided by Free Energy Relationship Analysis of Steric Parameters. Chemistry 2017; 23:5488-5497. [DOI: 10.1002/chem.201605666] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Chen Yang
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Jie Wang
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Yang Liu
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Xiang Ni
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Xin Li
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300071 P. R. China
| | - Jin‐Pei Cheng
- State Key Laboratory of Elemento-organic Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300071 P. R. China
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70
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Li Y, He CQ, Gao FX, Li Z, Xue XS, Li X, Houk KN, Cheng JP. Design and Applications of N-tert-Butyl Sulfinyl Squaramide Catalysts. Org Lett 2017; 19:1926-1929. [DOI: 10.1021/acs.orglett.7b00727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Yao Li
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Cyndi Qixin He
- Department of Chemistry and Biochemistry, University of California, Los
Angeles, California 90095, United States
| | - Fei-Xiang Gao
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Zhen Li
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xiao-Song Xue
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xin Li
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los
Angeles, California 90095, United States
| | - Jin-Pei Cheng
- State key Laboratory
of Elemento-Organic Chemistry, College of Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
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71
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Chennapuram M, Subba Reddy UV, Seki C, Okuyama Y, Kwon E, Uwai K, Tokiwa M, Takeshita M, Nakano H. Hybrid-Type Squaramide-Fused Amino Alcohol Organocatalysts for Enantioselective Nitro-Aldol Reaction of Nitromethane with Isatins. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700138] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Madhu Chennapuram
- Division of Sustainable and Environmental Engineering; Graduate School of Engineering; Muroran Institute of Technology; 27-1 Mizumoto 050-8585 Muroran Japan
| | - U. V. Subba Reddy
- Division of Sustainable and Environmental Engineering; Graduate School of Engineering; Muroran Institute of Technology; 27-1 Mizumoto 050-8585 Muroran Japan
| | - Chigusa Seki
- Division of Sustainable and Environmental Engineering; Graduate School of Engineering; Muroran Institute of Technology; 27-1 Mizumoto 050-8585 Muroran Japan
| | - Yuko Okuyama
- Tohoku Medical and Pharmaceutical University; 4-4-1 Komatsushima, Aoba-ku 981-8558 Sendai Japan
| | - Eunsang Kwon
- Research and Analytical Center for Giant Molecules; Graduate School of Sciences; Tohoku University; 6-3 Aoba, Aramaki, Aoba-ku 980-8578 Sendai Japan
| | - Koji Uwai
- Division of Sustainable and Environmental Engineering; Graduate School of Engineering; Muroran Institute of Technology; 27-1 Mizumoto 050-8585 Muroran Japan
| | - Michio Tokiwa
- Tokiwakai Group; 62 Numajiri, Tsuduri-chou Uchigo 973-8053 Iwaki Japan
| | | | - Hiroto Nakano
- Division of Sustainable and Environmental Engineering; Graduate School of Engineering; Muroran Institute of Technology; 27-1 Mizumoto 050-8585 Muroran Japan
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72
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Zhao B, Li J, Du D. Squaramide‐Catalyzed Asymmetric Reactions. CHEM REC 2017; 17:994-1018. [DOI: 10.1002/tcr.201600140] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/27/2017] [Indexed: 01/10/2023]
Affiliation(s)
- Bo‐Liang Zhao
- School of Chemistry and Chemical EngineeringBeijing Institute of Technology 5 South Zhongguancun Street Beijing 100081 People's Republic of China
| | - Jun‐Hua Li
- School of Chemistry and Chemical EngineeringBeijing Institute of Technology 5 South Zhongguancun Street Beijing 100081 People's Republic of China
| | - Da‐Ming Du
- School of Chemistry and Chemical EngineeringBeijing Institute of Technology 5 South Zhongguancun Street Beijing 100081 People's Republic of China
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73
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Xue XS, Wang Y, Li M, Cheng JP. Comprehensive Energetic Scale for Quantitatively Estimating the Fluorinating Potential of N–F Reagents in Electrophilic Fluorinations. J Org Chem 2016; 81:4280-9. [DOI: 10.1021/acs.joc.6b00683] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Jin-Pei Cheng
- Center
of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing 100084, China
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74
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Han X, Zhou HB, Dong C. Applications of Chiral Squaramides: From Asymmetric Organocatalysis to Biologically Active Compounds. CHEM REC 2016; 16:897-906. [DOI: 10.1002/tcr.201500266] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Xin Han
- State Key Laboratory of Virology; Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education Wuhan University School of Pharmaceutical Sciences; Wuhan 430071 P. R. China
| | - Hai-Bing Zhou
- State Key Laboratory of Virology; Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education Wuhan University School of Pharmaceutical Sciences; Wuhan 430071 P. R. China
| | - Chune Dong
- State Key Laboratory of Virology; Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education Wuhan University School of Pharmaceutical Sciences; Wuhan 430071 P. R. China
- Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences; Shanghai 200032 P. R. China
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75
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Kumarswamyreddy N, Kesavan V. Enantioselective Synthesis of Dihydrospiro[indoline-3,4′-pyrano[2,3-c]pyrazole] Derivatives via Michael/Hemiketalization Reaction. Org Lett 2016; 18:1354-7. [DOI: 10.1021/acs.orglett.6b00287] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nandarapu Kumarswamyreddy
- Chemical Biology Laboratory,
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Venkitasamy Kesavan
- Chemical Biology Laboratory,
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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76
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Wolf FF, Klare H, Goldfuss B. Asymmetric Michael Additions of 4-Hydroxycoumarin to β-Nitrostyrenes with Chiral, Bifunctional Hydrogen-Bonding Catalysts. J Org Chem 2016; 81:1762-8. [DOI: 10.1021/acs.joc.5b02167] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Florian F. Wolf
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany
| | - Helge Klare
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany
| | - Bernd Goldfuss
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany
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77
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Ni X, Li X, Cheng JP. Equilibrium acidities of cinchona alkaloid organocatalysts bearing 6′-hydrogen bonding donors in DMSO. Org Chem Front 2016. [DOI: 10.1039/c5qo00305a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The pKa values of 18 cinchona alkaloid based organocatalysts bearing 6′-hydrogen bonding donors were determined by the overlapping indicator method in DMSO via UV spectrophotometric titrations. The pKa values are in the range of 6.76–20.24.
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Affiliation(s)
- Xiang Ni
- State Key Laboratory of Elemento-Organic Chemistry
- Department of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Xin Li
- State Key Laboratory of Elemento-Organic Chemistry
- Department of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Jin-Pei Cheng
- Collaborative Innovation Center of Chemical Science and Engineering
- Tianjin 300071
- China
- Center of Basic Molecular Science
- Department of Chemistry
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78
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Nath I, Chakraborty J, Verpoort F. Metal organic frameworks mimicking natural enzymes: a structural and functional analogy. Chem Soc Rev 2016; 45:4127-70. [DOI: 10.1039/c6cs00047a] [Citation(s) in RCA: 299] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this review, we have portrayed the structure, synthesis and applications of a variety of biomimetic MOFs from an unprecedented angle.
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Affiliation(s)
- Ipsita Nath
- Laboratory of Organometallics
- Catalysis and Ordered Materials
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing
- Center for Chemical and Material Engineering
- Wuhan University of Technology
| | - Jeet Chakraborty
- Laboratory of Organometallics
- Catalysis and Ordered Materials
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing
- Center for Chemical and Material Engineering
- Wuhan University of Technology
| | - Francis Verpoort
- Laboratory of Organometallics
- Catalysis and Ordered Materials
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing
- Center for Chemical and Material Engineering
- Wuhan University of Technology
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79
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Held FE, Tsogoeva SB. Asymmetric cycloaddition reactions catalyzed by bifunctional thiourea and squaramide organocatalysts: recent advances. Catal Sci Technol 2016. [DOI: 10.1039/c5cy01894c] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this review, the recent developments in the field of enantioselective cycloaddition reactions using powerful bifunctional amine-thiourea and amine-squaramide organocatalysts have been described.
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Affiliation(s)
- Felix E. Held
- Department of Chemistry and Pharmacy
- Organic Chemistry Chair I and Interdisciplinary Center for Molecular Materials
- University of Erlangen-Nürnberg
- 91054 Erlangen
- Germany
| | - Svetlana B. Tsogoeva
- Department of Chemistry and Pharmacy
- Organic Chemistry Chair I and Interdisciplinary Center for Molecular Materials
- University of Erlangen-Nürnberg
- 91054 Erlangen
- Germany
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80
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Ni X, Li X, Li Z, Cheng JP. Equilibrium acidities of BINOL type chiral phenolic hydrogen bonding donors in DMSO. Org Chem Front 2016. [DOI: 10.1039/c6qo00252h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pKa values of fifteen BINOL type chiral phenolic catalysts were determined by the overlapping indicator method in DMSO via UV spectrophotometric titrations. The pKa values are in the range of 9.30–16.43.
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Affiliation(s)
- Xiang Ni
- State Key Laboratory of Elemento-Organic Chemistry
- Department of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Xin Li
- State Key Laboratory of Elemento-Organic Chemistry
- Department of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Zhen Li
- State Key Laboratory of Elemento-Organic Chemistry
- Department of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Jin-Pei Cheng
- Collaborative Innovation Center of Chemical Science and Engineering
- Tianjin 300071
- China
- Center of Basic Molecular Science
- Department of Chemistry
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81
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Sanna E, López C, Ballester P, Rotger C, Costa A. Unexpected Squaramide-Induced Cleavage of Benzils: Synthesis and Characterization of Mono-Aroyl Squarimides. European J Org Chem 2015. [DOI: 10.1002/ejoc.201501235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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82
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Experimental and Theoretical Studies in Hydrogen-Bonding Organocatalysis. Molecules 2015; 20:15500-24. [PMID: 26343615 PMCID: PMC6331831 DOI: 10.3390/molecules200915500] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 12/31/2022] Open
Abstract
Chiral thioureas and squaramides are among the most prominent hydrogen-bond bifunctional organocatalysts now extensively used for various transformations, including aldol, Michael, Mannich and Diels-Alder reactions. More importantly, the experimental and computational study of the mode of activation has begun to attract considerable attention. Various experimental, spectroscopic and calculation methods are now frequently used, often as an integrated approach, to establish the reaction mechanism, the mode of activation or explain the stereochemical outcome of the reaction. This article comprises several case studies, sorted according to the method used in their study. The aim of this review is to give the investigators an overview of the methods currently utilized for mechanistic investigations in hydrogen-bonding organocatalysis.
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83
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Gung BW, Schlitzer SC. Can hydrogen-bonding donors abstract chloride from LAu(I)Cl complexes: a computational study. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.07.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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84
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Affiliation(s)
- Takahiko Akiyama
- Department
of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
| | - Keiji Mori
- Department
of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
- Department
of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho Koganei, Tokyo 184-8588, Japan
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85
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Elmes RBP, Busschaert N, Czech DD, Gale PA, Jolliffe KA. pH switchable anion transport by an oxothiosquaramide. Chem Commun (Camb) 2015; 51:10107-10. [PMID: 25998008 DOI: 10.1039/c5cc03625a] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
An oxothiosquaramide was shown to bind to chloride through hydrogen bonding interactions in DMSO and found to exhibit pH switchable choride transport across phospholipid bilayers via an antiport transport mechanism.
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Affiliation(s)
- Robert B P Elmes
- School of Chemistry (F11), The University of Sydney, 2006 NSW, Australia.
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86
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Dong Z, Yan C, Gao Y, Dong C, Qiu G, Zhou HB. Tunable Bifunctional Phosphine-Squaramide Promoted Morita-Baylis-Hillman Reaction ofN-Alkyl Isatins with Acrylates. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500110] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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87
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Caruana L, Mondatori M, Corti V, Morales S, Mazzanti A, Fochi M, Bernardi L. Catalytic Asymmetric Addition of Meldrum’s Acid, Malononitrile, and 1,3-Dicarbonyls toortho-Quinone Methides Generated In Situ Under Basic Conditions. Chemistry 2015; 21:6037-41. [DOI: 10.1002/chem.201500710] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Indexed: 11/07/2022]
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88
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Li Z, Li X, Ni X, Cheng JP. Equilibrium Acidities of Proline Derived Organocatalysts in DMSO. Org Lett 2015; 17:1196-9. [DOI: 10.1021/acs.orglett.5b00143] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhen Li
- State Key Laboratory of Elemento-Organic
Chemistry, Department of Chemistry, Collaborative Innovation Center
of Chemical Science and Engineering, Nankai University, Weijin Road
94th, Tianjin 300071, China
| | - Xin Li
- State Key Laboratory of Elemento-Organic
Chemistry, Department of Chemistry, Collaborative Innovation Center
of Chemical Science and Engineering, Nankai University, Weijin Road
94th, Tianjin 300071, China
| | - Xiang Ni
- State Key Laboratory of Elemento-Organic
Chemistry, Department of Chemistry, Collaborative Innovation Center
of Chemical Science and Engineering, Nankai University, Weijin Road
94th, Tianjin 300071, China
| | - Jin-Pei Cheng
- State Key Laboratory of Elemento-Organic
Chemistry, Department of Chemistry, Collaborative Innovation Center
of Chemical Science and Engineering, Nankai University, Weijin Road
94th, Tianjin 300071, China
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89
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Bera K, Namboothiri INN. Quinine-derived thiourea and squaramide catalyzed conjugate addition of α-nitrophosphonates to enones: asymmetric synthesis of quaternary α-aminophosphonates. J Org Chem 2015; 80:1402-13. [PMID: 25569800 DOI: 10.1021/jo502332r] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Conjugate addition of α-nitrophosphonates to enones was carried out in the presence of two sets of organocatalysts, viz. a quinine-thiourea and a quinine-squaramide. The quinine-thiourea provided the products possessing an α-quaternary chiral center in high enantioselectivities only in the case of electron rich enones. On the other hand, the quinine-squaramide was more efficient in that a wide variety of electron rich and electron poor enones underwent Michael addition of nitrophosphonates to afford the quaternary α-nitrophosphonates in excellent yields and enantioselectivities. The hydrogen bonding donor ability of the bifunctional catalyst, as shown in the proposed transition states, appears primarily responsible for the observed selectivity. However, a favorable π-stacking between the aryl groups of thiourea/squaramide and aryl vinyl ketone also appeared favorable. The reaction was amenable to scale up, and the enantioenriched quaternary α-nitrophosphonates could be easily transformed to synthetically and biologically useful quaternary α-aminophosphonates and other multifunctional molecules.
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Affiliation(s)
- Kalisankar Bera
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400 076, India
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90
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Chauhan P, Mahajan S, Kaya U, Hack D, Enders D. Bifunctional Amine-Squaramides: Powerful Hydrogen-Bonding Organocatalysts for Asymmetric Domino/Cascade Reactions. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201401003] [Citation(s) in RCA: 412] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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91
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McGuirk CM, Katz MJ, Stern CL, Sarjeant AA, Hupp JT, Farha OK, Mirkin CA. Turning on catalysis: incorporation of a hydrogen-bond-donating squaramide moiety into a Zr metal-organic framework. J Am Chem Soc 2015; 137:919-25. [PMID: 25574688 DOI: 10.1021/ja511403t] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Herein, we demonstrate that the incorporation of an acidic hydrogen-bond-donating squaramide moiety into a porous UiO-67 metal-organic framework (MOF) derivative leads to dramatic acceleration of the biorelevant Friedel-Crafts reaction between indole and β-nitrostyrene. In comparison, it is shown that free squaramide derivatives, not incorporated into MOF architectures, have no catalytic activity. Additionally, using the UiO-67 template, we were able to perform a direct comparison of catalytic activity with that of the less acidic urea-based analogue. This is the first demonstration of the functionalization of a heterogeneous framework with an acidic squaramide derivative.
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Affiliation(s)
- C Michael McGuirk
- Department of Chemistry and the International Institute for Nanotechnology, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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92
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Liu J, Chen C, Li Z, Wu W, Zhi X, Zhang Q, Wu H, Wang X, Cui S, Guo K. A squaramide and tertiary amine: an excellent hydrogen-bonding pair organocatalyst for living polymerization. Polym Chem 2015. [DOI: 10.1039/c5py00508f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A hydrogen-bond motif based on a squaramide and sparteine efficiently promoted the ring-opening polymerization of l-lactide at ambient temperature.
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93
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Walvoord RR, Huynh PNH, Kozlowski MC. Quantification of electrophilic activation by hydrogen-bonding organocatalysts. J Am Chem Soc 2014; 136:16055-65. [PMID: 25325850 PMCID: PMC4235367 DOI: 10.1021/ja5086244] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
A spectrophotometric sensor is described
that provides a useful
assessment of the LUMO-lowering provided by catalysts in Diels–Alder
and Friedel–Crafts reactions. A broad range of 33 hydrogen-bonding
catalysts was assessed with the sensor, and the relative rates in
the above reactions spanned 5 orders of magnitude as determined via 1H- and 2H NMR spectroscopic measurements, respectively.
The differences between the maximum wavelength shift of the sensor
with and without catalyst (Δλmax–1) were found to correlate linearly with ln(krel) values for both reactions, even though the substrate feature
that interacts with the catalyst differs significantly (ketone vs
nitro). The sensor provides an assessment of both the inherent
reactivity of a catalyst architecture as well as the sensitivity of the reaction to changes within an architecture.
In contrast, catalyst pKa values are a
poor measure of reactivity, although correlations have been identified
within catalyst classes.
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Affiliation(s)
- Ryan R Walvoord
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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94
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Du H, Rodriguez J, Bugaut X, Constantieux T. Organocatalytic enantio- and diastereoselective conjugate addition to nitroolefins: when β-ketoamides surpass β-ketoesters. Chemistry 2014; 20:8458-66. [PMID: 24895115 DOI: 10.1002/chem.201402192] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Indexed: 12/28/2022]
Abstract
Our findings on the bifunctional squaramide-catalyzed enantioselective conjugate addition of β-ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene β-ketoamides, unlike the extensively studied β-ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted to rationalize the observed reactivity and selectivity. The high level of diastereocontrol, along with the amenability of the amide group to postfunctionalization, dramatically increase the synthetic usefulness of the transformation.
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Affiliation(s)
- Haiying Du
- Aix Marseille Université, Centrale Marseille, CNRS iSm2 UMR 7313, 13397, Marseille (France), Fax: (+33) 491-289-187
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95
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Busschaert N, Elmes RBP, Czech DD, Wu X, Kirby IL, Peck EM, Hendzel KD, Shaw SK, Chan B, Smith BD, Jolliffe KA, Gale PA. Thiosquaramides: pH switchable anion transporters. Chem Sci 2014; 5:3617-3626. [PMID: 26146535 DOI: 10.1039/c4sc01629g] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The transport of anions across cellular membranes is an important biological function governed by specialised proteins. In recent years, many small molecules have emerged that mimick the anion transport behaviour of these proteins, but only a few of these synthetic molecules also display the gating/switching behaviour seen in biological systems. A small series of thiosquaramides was synthesised and their pH-dependent chloride binding and anion transport behaviour was investigated using 1H NMR titrations, single crystal X-ray diffraction and a variety of vesicle-based techniques. Spectrophotometric titrations and DFT calculations revealed that the thiosquaramides are significantly more acidic than their oxosquaramide analogues, with pKa values between 4.0 and 9.0. This led to the observation that at pH 7.2 the anion transport ability of the thiosquaramides is fully switched OFF due to deprotonation of the receptor, but is completely switched ON at lower pH.
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Affiliation(s)
| | - Robert B P Elmes
- School of Chemistry (F11), The University of Sydney, 2006 NSW, Australia
| | - Dawid D Czech
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Xin Wu
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | | | - Evan M Peck
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Kevin D Hendzel
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Scott K Shaw
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Bun Chan
- School of Chemistry (F11), The University of Sydney, 2006 NSW, Australia
| | - Bradley D Smith
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Katrina A Jolliffe
- School of Chemistry (F11), The University of Sydney, 2006 NSW, Australia
| | - Philip A Gale
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK ; Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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