1
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Bara‐Estaún A, Harder MC, Lyall CL, Lowe JP, Suturina E, Hintermair U. Paramagnetic Relaxation Agents for Enhancing Temporal Resolution and Sensitivity in Multinuclear FlowNMR Spectroscopy. Chemistry 2023; 29:e202300215. [PMID: 36946535 PMCID: PMC10962566 DOI: 10.1002/chem.202300215] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/22/2023] [Accepted: 03/22/2023] [Indexed: 03/23/2023]
Abstract
Sensitivity in FlowNMR spectroscopy for reaction monitoring often suffers from low levels of pre-magnetisation due to limited residence times of the sample in the magnetic field. While this in-flow effect is tolerable for high sensitivity nuclei such as 1 H and 19 F, it significantly reduces the signal-to-noise ratio in 31 P and 13 C spectra, making FlowNMR impractical for low sensititvity nuclei at low concentrations. Paramagnetic relaxation agents (PRAs), which enhance polarisation and spin-lattice relaxation, could eliminate the adverse in-flow effect and improve the signal-to-noise ratio. Herein, [Co(acac)3 ], [Mn(acac)3 ], [Fe(acac)3 ], [Cr(acac)3 ], [Ni(acac)2 ]3, [Gd(tmhd)3 ] and [Cr(tmhd)3 ] are investigated for their effectiveness in improving signal intensity per unit time in FlowNMR applications under the additional constraint of chemical inertness towards catalytically active transition metal complexes. High-spin Cr(III) acetylacetonates emerged as the most effective compounds, successfully reducing 31 P T1 values four- to five-fold at PRA concentrations as low as 10 mM without causing adverse line broadening. Whereas [Cr(acac)3 ] showed signs of chemical reactivity with a mixture of triphenylphosphine, triphenylphosphine oxide and triphenylphosphate over the course of several hours at 80° C, the bulkier [Cr(tmhd)3 ] was stable and equally effective as a PRA under these conditions. Compatibility with a range of representative transition metal complexes often used in homogeneous catalysis has been investigated, and application of [Cr(tmhd)3 ] in significantly improving 1 H and 31 P{1 H} FlowNMR data quality in a Rh-catalysed hydroformylation reaction has been demonstrated. With the PRA added, 13 C relaxation times were reduced more than six-fold, allowing quantitative reaction monitoring of substrate consumption and product formation by 13 C{1 H} FlowNMR spectroscopy at natural abundance.
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Affiliation(s)
- Alejandro Bara‐Estaún
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Marie C. Harder
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Catherine L. Lyall
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - John P. Lowe
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
| | - Elizaveta Suturina
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
| | - Ulrich Hintermair
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUnited Kingdom
- Dynamic Reaction Monitoring FacilityUniversity of Bath, Claverton DownBathBA2 7AYUnited Kingdom
- Institute for SustainabilityUniversity of BathBathBA2 7AYUnited Kingdom
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2
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Sun BB, Liu K, Gao Q, Fang W, Lu S, Wang CR, Yao CZ, Cao HQ, Yu J. Enantioselective Ugi and Ugi-azide reactions catalyzed by anionic stereogenic-at-cobalt(III) complexes. Nat Commun 2022; 13:7065. [PMID: 36400776 PMCID: PMC9674650 DOI: 10.1038/s41467-022-34887-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 11/10/2022] [Indexed: 11/19/2022] Open
Abstract
Ugi reactions and related variations are proven to be atom and step-economic strategies for construction of highly valuable peptide-like skeletons and nitrogenous heterocycles. The development of structurally diverse range of novel catalytic systems and the discovery of new approaches to accommodate a broader scope of terminating reagents for asymmetric Ugi four-component reaction is still in high demand. Here, we report a strategy that enables enantioselective Ugi four-component and Ugi-azide reactions employing anionic stereogenic-at-cobalt(III) complexes as catalysts. The key nitrilium intermediates, generated through the nucleophilic addition of isocyanides to the chiral ion-pair which consists of stereogenic-at-cobalt(III) complexes counteranion and a protonated iminium, are trapped by either carboxylic acids or in situ-generated hydrazoic acid, delivering α-acylamino amides and α-aminotetrazoles in good to excellent enantioselectivities (up to 99:1 e.r.).
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Affiliation(s)
- Bing-Bing Sun
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Kun Liu
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Quan Gao
- grid.411389.60000 0004 1760 4804School of Plant Protection, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, and Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Agricultural University, Hefei, 230036 China
| | - Wei Fang
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Shuang Lu
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Chun-Ru Wang
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Chuan-Zhi Yao
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China
| | - Hai-Qun Cao
- grid.411389.60000 0004 1760 4804School of Plant Protection, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, and Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Agricultural University, Hefei, 230036 China
| | - Jie Yu
- grid.411389.60000 0004 1760 4804Department of Applied Chemistry, Anhui Agricultural University, Hefei, 230036 China ,grid.411389.60000 0004 1760 4804School of Plant Protection, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, and Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Agricultural University, Hefei, 230036 China
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3
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Cobo J, Molina S, Sánchez A, Nogueras M, Insuasty B, Orozco‐López F. Reactivity of Pyrimidinylphosphazenes with Acetylenic Esters: Competitive [4+2] and [2+2] Tandem Cycloaddition/Retro‐cycloaddition Approaches. J Heterocycl Chem 2022. [DOI: 10.1002/jhet.4487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Justo Cobo
- Departamento de Química Inorgánica y Orgánica Grupo de Investigación en Compuestos de Interés Biológico, Universidad de Jaén Jaén Spain
| | - Sebastián Molina
- Departamento de Química Inorgánica y Orgánica Grupo de Investigación en Compuestos de Interés Biológico, Universidad de Jaén Jaén Spain
| | - Adolfo Sánchez
- Departamento de Química Inorgánica y Orgánica Grupo de Investigación en Compuestos de Interés Biológico, Universidad de Jaén Jaén Spain
| | - Manuel Nogueras
- Departamento de Química Inorgánica y Orgánica Grupo de Investigación en Compuestos de Interés Biológico, Universidad de Jaén Jaén Spain
| | - Braulio Insuasty
- Departamento de Química Grupo de Investigación de Compuestos Heterocíclicos, Universidad del Valle Cali Colombia
| | - Fabián Orozco‐López
- Grupo de Estudios en Síntesis y Aplicaciones de Compuestos Heterocíclicos, Departamento de Química, Universidad Nacional de Colombia Bogotá Colombia
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4
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Wei R, Hall AMR, Behrens R, Pritchard MS, King EJ, Lloyd‐Jones GC. Stopped‐Flow
19
F NMR Spectroscopic Analysis of a Protodeboronation Proceeding at the Sub‐Second Time‐Scale. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100290] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Ran Wei
- School of Chemistry The University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| | - Andrew M. R. Hall
- School of Chemistry The University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| | - Richard Behrens
- Laboratory of Engineering Thermodynamics (LTD) Technische Universität Kaiserslautern Erwin-Schrödinger-Straße 44 Kaiserslautern 67663 Germany
| | | | - Edward J. King
- TgK Scientific Ltd. Bradford on Avon Wiltshire BA15 1DH UK
| | - Guy C. Lloyd‐Jones
- School of Chemistry The University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
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5
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Shaik MS, Nadiveedhi MR, Gundluru M, Narreddy AKR, Thathireddy KR, Ramakrishna R, Cirandur SR. 2‐Amino‐3‐cyano‐4H
‐chromene‐4‐ylphosphonates as potential antiviral agents: Synthesis, in ovo and in silico approach. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | - Mohan Gundluru
- Department of Chemistry Sri Venkateswara University Tirupati India
- DST‐PURSE Centre Sri Venkateswara University Tirupati India
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6
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Mechanistic investigation on the remote stereocontrol in the chiral Lewis base-catalyzed, SiCl4-promoted kinetic resolution of chlorinated cis-vinyl epoxides. Tetrahedron 2021. [DOI: 10.1016/j.tet.2020.131763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Fu Y, Bergbreiter DE. Recyclable Polyisobutylene‐Bound HMPA as an Organocatalyst in Recyclable Poly(α‐olefin) Solvents. ChemCatChem 2020. [DOI: 10.1002/cctc.202001207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ying‐Hua Fu
- Department of Chemistry Texas A&M University P.O. Box 30012, College Station 77842-3012 Texas USA
| | - David E. Bergbreiter
- Department of Chemistry Texas A&M University P.O. Box 30012, College Station 77842-3012 Texas USA
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8
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Kotani S, Nakajima M. Asymmetric cross-Aldol Reactions between Two Carbonyl Compounds Catalyzed by Chiral Phosphine Oxides. J SYN ORG CHEM JPN 2020. [DOI: 10.5059/yukigoseikyokaishi.78.1163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shunsuke Kotani
- Graduate School of Pharmaceutical Sciences, Kumamoto University
| | - Makoto Nakajima
- Graduate School of Pharmaceutical Sciences, Kumamoto University
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9
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Davis AJ, Watson RB, Nasrallah DJ, Gomez-Lopez JL, Schindler CS. Superelectrophilic aluminium(iii)–ion pairs promote a distinct reaction path for carbonyl–olefin ring-closing metathesis. Nat Catal 2020. [DOI: 10.1038/s41929-020-00499-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Kowalke J, Wagler J, Viehweger C, Brendler E, Kroke E. Ionic Dissociation of SiCl 4 : Formation of [SiL 6 ]Cl 4 with L=Dimethylphosphinic Acid. Chemistry 2020; 26:8003-8006. [PMID: 32511798 PMCID: PMC7383495 DOI: 10.1002/chem.202000435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/01/2020] [Indexed: 11/12/2022]
Abstract
Reactions of SiCl4 with R2PO(OH) (R=Me, Cl) yield compounds with six‐fold coordinated silicon atoms. Whereas R=Me afforded the hexacoordinated tetra‐cationic silicon complex [Si(Me2PO(OH))6]4+ with chloride counter‐ions, R=Cl caused release of HCl with formation of a cyclic dimeric silicon complex [Si(Cl2PO(OH))(Cl2PO2)3(μ‐Cl2PO2)]2 with bridging bidentate dichlorophosphates.
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Affiliation(s)
- Janine Kowalke
- Technische Universität Bergakademie Freiberg, Department of Chemistry and Physics, Institute of Inorganic Chemistry, Leipziger Straße 29, 09599, Freiberg, Germany
| | - Jörg Wagler
- Technische Universität Bergakademie Freiberg, Department of Chemistry and Physics, Institute of Inorganic Chemistry, Leipziger Straße 29, 09599, Freiberg, Germany
| | - Christine Viehweger
- Technische Universität Bergakademie Freiberg, Department of Chemistry and Physics, Institute of Analytical Chemistry, Leipziger Straße 29, 09599, Freiberg, Germany
| | - Erica Brendler
- Technische Universität Bergakademie Freiberg, Department of Chemistry and Physics, Institute of Analytical Chemistry, Leipziger Straße 29, 09599, Freiberg, Germany
| | - Edwin Kroke
- Technische Universität Bergakademie Freiberg, Department of Chemistry and Physics, Institute of Inorganic Chemistry, Leipziger Straße 29, 09599, Freiberg, Germany
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11
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Rossi S, Benaglia M, Raimondi LM. DFT investigation on Lewis base-catalyzed Lewis acid-mediated reactions: hypervalent silicon species as chiral organocatalysts in (direct) aldol reactions. NEW J CHEM 2020. [DOI: 10.1039/d0nj03976d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The stereoselective organocatalytic addition of silyl enol ethers to aromatic aldehydes catalyzed by bisphosphoramides and the direct aldol reaction between ketones and aromatic aldehydes promoted by phosphinoxides in the presence of tetrachlorosilane were investigated by the DFT approach.
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Affiliation(s)
- Sergio Rossi
- Department of Chemistry
- Università degli Studi di Milano
- 20133 Milano
- Italy
| | - Maurizio Benaglia
- Department of Chemistry
- Università degli Studi di Milano
- 20133 Milano
- Italy
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12
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Mirco AV, Maurizio B, Sergio R, Tiziana B, Roberto C, Marco P. TetraPh-Tol-BITIOPO: a new atropisomeric 3,3'-bithiophene based phosphine oxide as an organocatalyst in Lewis base-catalyzed Lewis acid mediated reactions. Org Biomol Chem 2019; 17:7474-7481. [PMID: 31361281 DOI: 10.1039/c9ob01297d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new chiral phosphine oxide based on a 3,3'-bithiophene scaffold (TetraPh-Tol-BITIOPO) was synthesized, fully characterized and separated into antipodes through chiral HPLC. This new compound was successfully employed as an organocatalyst in Lewis base-catalyzed Lewis acid mediated reactions involving trichlorosilyl compounds. The new atropisomeric catalyst was able to promote the allylation of aldehydes with allyltrichlorosilane in up to 98% yield and up to 96% enantiomeric excess (ee), and the direct aldol reaction to afford β-hydroxy ketones and β-hydroxy thioesters, with good chemical yields and modest stereochemical efficiency. Computational studies helped to elucidate and to rationalize the stereochemical outcome of the reactions catalyzed by TetraPh-Tol-BITIOPO that was found to favour the formation of the isomer with an opposite absolute configuration in comparison with the products obtained with the previously reported 3,3'-bithiophene-based catalyst.
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Affiliation(s)
- Abbinante Vincenzo Mirco
- Dipartimento di Scienza ed Alta Tecnologia dell'Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy
| | - Benaglia Maurizio
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
| | - Rossi Sergio
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
| | - Benincori Tiziana
- Dipartimento di Scienza ed Alta Tecnologia dell'Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy
| | - Cirilli Roberto
- Centro Nazionale per il Controllo e la Valutazione dei Farmaci, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy
| | - Pierini Marco
- Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma "La Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy
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13
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Kotani S. Phosphine Oxide-Catalyzed Asymmetric Aldol Reactions and Double Aldol Reactions. Chem Pharm Bull (Tokyo) 2019; 67:519-526. [PMID: 31155556 DOI: 10.1248/cpb.c19-00015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chiral phosphine oxides successfully catalyze asymmetric cross-aldol reactions of various carbonyl compounds in a highly enantioselective manner. The phosphine oxide catalysts coordinate to chlorosilanes to form chiral hypervalent silicon complexes in situ, which activate both aldol donors and acceptors, thus realizing cross-aldol reactions between a ketone and an aldehyde, between two aldehydes, between two ketones, and of 2,6-diketones. The use of phosphine oxide catalysis can be further extended to achieve the first catalytic enantioselective double aldol reactions, realizing one-pot stereoselective construction of up to four stereogenic centers.
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Affiliation(s)
- Shunsuke Kotani
- Priority Organization for Innovation and Excellence Kumamoto University.,Graduate School of Pharmaceutical Sciences, Kumamoto University
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14
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Li J, Li Y, Sun J, Gui Y, Huang Y, Zha Z, Wang Z. Copper-catalyzed enantioselective Mukaiyama aldol reaction of silyl enol ethers with isatins. Chem Commun (Camb) 2019; 55:6309-6312. [PMID: 31089588 DOI: 10.1039/c9cc02159k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A highly enantioselective Mukaiyama aldol reaction of silyl enol ethers with isatins catalyzed by chiral copper complexes was developed. A series of chiral 3-substituted 3-hydroxy-2-oxindoles bearing a tetra-substituted center could be obtained exclusively with high yields (up to 95%) and excellent enantioselectivities (up to 99%). In particular, water was essential to improve the diastereoselectivity.
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Affiliation(s)
- Jindong Li
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry & Center for Excellence in Molecular Synthesis of Chinese Academy of Sciences, Collaborative Innovation Center of Suzhou Nano Science and Technology & School of Chemistry and Materials Science in University of Science and Technology of China, Hefei, 230026, P. R. China.
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15
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Yasuda M, Saga Y, Tokunaga T, Itoh S, Aoki S. Stereoselective aldol reactions of dihydroxyacetone derivatives catalyzed by chiral Zn2+ complexes. Tetrahedron 2019. [DOI: 10.1016/j.tet.2018.12.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Wagner GE, Tassoti S, Glanzer S, Stadler E, Herges R, Gescheidt G, Zangger K. Monitoring fast chemical processes by reaction-interrupted excitation transfer (ExTra) NMR spectroscopy. Chem Commun (Camb) 2019; 55:12575-12578. [DOI: 10.1039/c9cc06427c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ExTra NMR utilises selectively inverted magnetisation for in situ monitoring of fast chemical processes.
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Affiliation(s)
- Gabriel E. Wagner
- Institute of Hygiene
- Microbiology and Environmental Medicine
- Medical University of Graz
- A 8010 Graz
- Austria
| | - Sebastian Tassoti
- Institute of Chemistry
- Organic and Bioorganic Chemistry
- University of Graz
- A-8010 Graz
- Austria
| | - Simon Glanzer
- Institute of Chemistry
- Organic and Bioorganic Chemistry
- University of Graz
- A-8010 Graz
- Austria
| | - Eduard Stadler
- Institute of Physical and Theoretical Chemistry
- Graz University of Technology
- A-8010 Graz
- Austria
| | - Rainer Herges
- Otto Diels Institute for Organic Chemistry
- University of Kiel
- Otto-Hahn-Platz 4
- DE-24118 Kiel
- Germany
| | - Georg Gescheidt
- Institute of Physical and Theoretical Chemistry
- Graz University of Technology
- A-8010 Graz
- Austria
| | - Klaus Zangger
- Institute of Chemistry
- Organic and Bioorganic Chemistry
- University of Graz
- A-8010 Graz
- Austria
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17
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Reep C, Morgante P, Peverati R, Takenaka N. Axial-Chiral Biisoquinoline N, N'-Dioxides Bearing Polar Aromatic C-H Bonds as Catalysts in Sakurai-Hosomi-Denmark Allylation. Org Lett 2018; 20:5757-5761. [PMID: 30199262 DOI: 10.1021/acs.orglett.8b02457] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The design, synthesis, and evaluation of axial-chiral biisoquinolines bearing polar aromatic C-H bonds as Lewis base catalysts are reported. Lewis bases containing the 3,5-bis(trifluoromethyl)phenyl group were found to be significantly more enantioselective for a wider range of substrates than those bearing aromatic residues that are not strongly electron-deficient in the allylation of aldehydes with allyltrichlorosilane. Also, optically pure 3,3'-dibromo-1,1'-biisoquinoline N, N'-dioxide that has not been previously reported was synthesized as a common catalyst precursor to facilitate the study.
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18
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Böse D, Denmark SE. Investigating the Enantiodetermining Step of a Chiral Lewis Base Catalyzed Bromocycloetherification of Privileged Alkenes. Synlett 2018; 29:433-439. [PMID: 29904236 DOI: 10.1055/s-0036-1590951] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The development of catalytic, enantioselective halofunctionalizations of unactivated alkenes has made significant progress in recent years. However, the identification of generally applicable catalysts for wide range of substrates has yet to be realized. A detailed understanding of the reaction mechanism is essential to guide the formulation of a truly general catalyst. Herein, we present our investigations on the enantiodetermining step of a Lewis base catalyzed bromocycloetherification that provides important insights and design criteria.
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Affiliation(s)
- Dietrich Böse
- University of Illinois at Urbana-Champaign, Department of Chemistry, 600 S Mathews Ave., Urbana, IL 61801, USA
| | - Scott E Denmark
- University of Illinois at Urbana-Champaign, Department of Chemistry, 600 S Mathews Ave., Urbana, IL 61801, USA
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19
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Yamashita Y, Yasukawa T, Yoo WJ, Kitanosono T, Kobayashi S. Catalytic enantioselective aldol reactions. Chem Soc Rev 2018; 47:4388-4480. [DOI: 10.1039/c7cs00824d] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent developments in catalytic asymmetric aldol reactions have been summarized.
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Affiliation(s)
- Yasuhiro Yamashita
- Department of Chemistry
- School of Science
- The University of Tokyo
- Bunkyo-ku
- Japan
| | - Tomohiro Yasukawa
- Department of Chemistry
- School of Science
- The University of Tokyo
- Bunkyo-ku
- Japan
| | - Woo-Jin Yoo
- Department of Chemistry
- School of Science
- The University of Tokyo
- Bunkyo-ku
- Japan
| | - Taku Kitanosono
- Department of Chemistry
- School of Science
- The University of Tokyo
- Bunkyo-ku
- Japan
| | - Shū Kobayashi
- Department of Chemistry
- School of Science
- The University of Tokyo
- Bunkyo-ku
- Japan
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20
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Koroniak-Szejn K, Tomaszewska J, Koroniak H. The synthesis of new fluorinated or nonfluorinated sugar phosphonates and phosphoramidates as building blocks in the synthesis of modified hyaluronic acid subunits. PHOSPHORUS SULFUR 2017. [DOI: 10.1080/10426507.2017.1311332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | | | - Henryk Koroniak
- Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland
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21
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Zhang P, Liu J, Wang Z, Ding K. Highly enantio- and diastereoselective reductive aldol reactions catalyzed by chiral spiro bisphosphine oxides. CHINESE JOURNAL OF CATALYSIS 2015. [DOI: 10.1016/s1872-2067(14)60241-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Niklas T, Stalke D, John M. Single-shot titrations and reaction monitoring by slice-selective NMR spectroscopy. Chem Commun (Camb) 2015; 51:1275-7. [DOI: 10.1039/c4cc08329f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time into space: the progress of a reaction is mapped onto an instant series of spatially resolved NMR spectra.
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Affiliation(s)
- T. Niklas
- Institut für Anorganische Chemie
- Georg-August-Universität Göttingen
- 37077 Göttingen
- Germany
| | - D. Stalke
- Institut für Anorganische Chemie
- Georg-August-Universität Göttingen
- 37077 Göttingen
- Germany
| | - M. John
- Institut für Anorganische Chemie
- Georg-August-Universität Göttingen
- 37077 Göttingen
- Germany
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23
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Denmark SE, Wilson TW, Burk MT. Enantioselective construction of quaternary stereogenic carbon atoms by the Lewis base catalyzed additions of silyl ketene imines to aldehydes. Chemistry 2014; 20:9268-79. [PMID: 25043283 DOI: 10.1002/chem.201403342] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Indexed: 11/07/2022]
Abstract
Silyl ketene imines derived from a variety of α-branched nitriles have been developed as highly useful reagents for the construction of quaternary stereogenic centers via the aldol addition reaction. In the presence of SiCl4 and the catalytic action of a chiral phosphoramide, silyl ketene imines undergo extremely rapid and high yielding addition to a wide variety of aromatic aldehydes with excellent diastereo- and enantioselectivity. Of particular note are the high yields and selectivities obtained from electron-rich, electron-poor, and hindered aldehydes. Linear aliphatic aldehydes did react with good diastereo- and enantioselectivity in the presence of nBu4N(+)I(-), but branched aldehydes were much less reactive. Semiempirical calculations provided a rationalization of the observed diastereo- and enantioselectivity via open transitions states.
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Affiliation(s)
- Scott E Denmark
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801 (USA), Fax: (+1) 217-333-3984.
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24
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25
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Sutar RL, Joshi NN. Base-catalyzed Mukaiyama-type aldol additions, a continued quest for stereoselectivity. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.tetasy.2013.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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26
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Zhang P, Han Z, Wang Z, Ding K. Spiro[4,4]-1,6-Nonadiene-Based Diphosphine Oxides in Lewis Base Catalyzed Asymmetric Double-Aldol Reactions. Angew Chem Int Ed Engl 2013; 52:11054-8. [DOI: 10.1002/anie.201305846] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Indexed: 11/11/2022]
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27
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Zhang P, Han Z, Wang Z, Ding K. Spiro[4,4]-1,6-Nonadiene-Based Diphosphine Oxides in Lewis Base Catalyzed Asymmetric Double-Aldol Reactions. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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Beutner GL, Denmark SE. Lewis base catalysis of the Mukaiyama directed aldol reaction: 40 years of inspiration and advances. Angew Chem Int Ed Engl 2013; 52:9086-96. [PMID: 23843275 PMCID: PMC7928217 DOI: 10.1002/anie.201302084] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Indexed: 11/05/2022]
Abstract
Since the landmark publications of the first directed aldol addition reaction in 1973, the site, diastereo-, and enantioselective aldol reaction has been elevated to the rarefied status of being both a named and a strategy-level reaction (the Mukaiyama directed aldol reaction). The importance of this reaction in the stereoselective synthesis of untold numbers of organic compounds, both natural and unnatural, cannot be overstated. However, its impact on the field extends beyond the impressive applications in synthesis. The directed aldol reaction has served as a fertile proving ground for new concepts and new methods for stereocontrol and catalysis. This Minireview provides a case history of how the challenges of merging site selectivity, diastereoselectivity, enantioselectivity, and catalysis into a unified reaction manifold stimulated the development of Lewis base catalyzed aldol addition reactions. The evolution of this process is chronicled from the authors' laboratories as well as in those of Professor Teruaki Mukaiyama.
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Affiliation(s)
- Gregory L. Beutner
- Bristol-Myers Squibb, Process Research & Development New Brunswick, NJ 08903 (USA)
| | - Scott E. Denmark
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana, IL 61801 (USA)
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29
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Beutner GL, Denmark SE. Lewis‐Base‐Katalyse der gerichteten Mukaiyama‐Aldolreaktion: 40 Jahre Inspiration und Fortschritt. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Gregory L. Beutner
- Bristol‐Myers Squibb, Process Research & Development, New Brunswick, NJ 08903 (USA)
| | - Scott E. Denmark
- Department of Chemistry, University of Illinois at Urbana‐Champaign, Urbana, IL 61801 (USA) http://www.scs.illinois.edu/denmark
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30
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Genoni A, Benaglia M, Rossi S, Celentano G. Enantiomerically Pure Bithiophene Diphosphine Oxides as Catalysts for Direct Double Aldol Reactions. Chirality 2013; 25:643-7. [DOI: 10.1002/chir.22190] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/25/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Andrea Genoni
- Dipartimento di Chimica; Universita' degli Studi di Milano; Milano Italy
| | - Maurizio Benaglia
- Dipartimento di Chimica; Universita' degli Studi di Milano; Milano Italy
| | - Sergio Rossi
- Dipartimento di Chimica; Universita' degli Studi di Milano; Milano Italy
| | - Giuseppe Celentano
- Dipartimento di Scienze Farmaceutiche; Universita' degli Studi di Milano; Milano Italy
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31
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Chandra Sheker Reddy A, Chen Z, Hatanaka T, Minami T, Hatanaka Y. Synthesis of Silaoxazolinium Salts Bearing Weakly Coordinating Anions: Structures and Catalytic Activities in the Aldol Reaction. Organometallics 2013. [DOI: 10.1021/om400017f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Anugu Chandra Sheker Reddy
- National Institute of Advanced Industrial Science and Technology, Tsukuba
Central 5, Tsukuba, Ibaraki, 305-8565, Japan
| | - Zhang Chen
- National Institute of Advanced Industrial Science and Technology, Tsukuba
Central 5, Tsukuba, Ibaraki, 305-8565, Japan
| | - Tohru Hatanaka
- Department of
Applied Chemistry, Graduate School of
Engineering, Osaka City University, Osaka
558-8585, Japan
| | - Tatsuya Minami
- Department of
Applied Chemistry, Graduate School of
Engineering, Osaka City University, Osaka
558-8585, Japan
| | - Yasuo Hatanaka
- Department of
Applied Chemistry, Graduate School of
Engineering, Osaka City University, Osaka
558-8585, Japan
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32
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Das S, Goswami A, Murali N, Asefa T. Efficient Tertiary Amine/Weak Acid Bifunctional Mesoporous Silica Catalysts for Michael Addition Reactions. ChemCatChem 2013. [DOI: 10.1002/cctc.201200551] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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33
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Wagner GE, Sakhaii P, Bermel W, Zangger K. Monitoring fast reactions by spatially-selective and frequency-shifted continuous NMR spectroscopy: application to rapid-injection protein unfolding. Chem Commun (Camb) 2013; 49:3155-7. [DOI: 10.1039/c3cc39107h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Peng Z, Takenaka N. Applications of Helical-Chiral Pyridines as Organocatalysts in Asymmetric Synthesis. CHEM REC 2012; 13:28-42. [DOI: 10.1002/tcr.201200010] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Indexed: 11/09/2022]
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35
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Monaco G, Vignes C, De Piano F, Bosco A, Massa A. Chiral sulfoxides in the enantioselective allylation of aldehydes with allyltrichlorosilane: a kinetic study. Org Biomol Chem 2012; 10:9650-9. [PMID: 23139050 DOI: 10.1039/c2ob27022f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanism of the allylation of aldehydes in the presence of allyltrichlorosilane employing the commercially available (R)-methyl p-tolyl sulfoxide as a Lewis base has been investigated. The combination of kinetic measurements, conductivity analysis and quantum chemical calculations indicates that the reaction proceeds through a dissociative pathway in which an octahedral cationic complex with two sulfoxides is involved. The lack of turnover is ascribed to the formation of neutral sulfurane derivatives.
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Affiliation(s)
- Guglielmo Monaco
- Dipartimento di Chimica e Biologia, Università di Salerno, Via Ponte Don Melillo, 84084 - Fisciano, SA, Italy.
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36
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Guo F, Wang L, Mao S, Zhang C, Yu J, Han J. Cationic bromonium complex: NBS/P(OPh)3 as an efficient catalyst for Nazarov cyclization. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.06.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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37
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The Interplay of Invention, Observation, and Discovery in the Development of Lewis Base Activation of Lewis Acids for Catalytic Enantioselective Synthesis. TOP ORGANOMETAL CHEM 2012. [DOI: 10.1007/3418_2012_43] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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38
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Denmark SE, Wilson TW. Lewis Base Catalyzed Enantioselective Additions of an N-Silyl Vinylketene Imine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108795] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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39
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Denmark SE, Wilson TW. Lewis base catalyzed enantioselective additions of an N-silyl vinylketene imine. Angew Chem Int Ed Engl 2012; 51:3236-9. [PMID: 22351382 DOI: 10.1002/anie.201108795] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/23/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Scott E Denmark
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA.
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40
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Kolla SR, Lee YR. Efficient one-pot synthesis of β-phosphono malonates and 2-amino-4H-chromen-4-ylphosphonate derivatives by ethylenediamine diacetate-catalyzed three-component reactions. Tetrahedron 2012. [DOI: 10.1016/j.tet.2011.10.060] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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41
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Rassu G, Zambrano V, Tanca R, Sartori A, Battistini L, Zanardi F, Curti C, Casiraghi G. 3-Alkenyl-2-silyloxyindoles: An Enabling, Yet Understated Progeny of Vinylogous Carbon Nucleophiles. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101446] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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42
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Zambrana J, Romea P, Urpí F, Luján C. Highly Stereoselective Titanium-Mediated Aldol Reaction from (S)-4-Benzyloxy-3-methyl-2-butanone. J Org Chem 2011; 76:8575-87. [DOI: 10.1021/jo201021z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joana Zambrana
- Departament de Química Orgànica, Universitat de Barcelona, Carrer Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain
| | - Pedro Romea
- Departament de Química Orgànica, Universitat de Barcelona, Carrer Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain
| | - Fèlix Urpí
- Departament de Química Orgànica, Universitat de Barcelona, Carrer Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain
| | - Cristina Luján
- Departament de Química Orgànica, Universitat de Barcelona, Carrer Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain
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43
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Trichlorosilyl triflate for enantioselective direct-type aldol reaction with chiral phosphine oxide. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.03.095] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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44
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Schenker S, Zamfir A, Freund M, Tsogoeva SB. Developments in Chiral Binaphthyl‐Derived Brønsted/Lewis Acids and Hydrogen‐Bond‐Donor Organocatalysis. European J Org Chem 2011. [DOI: 10.1002/ejoc.201001538] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sebastian Schenker
- Department of Chemistry and Pharmacy Chair of Organic Chemistry I University of Erlangen‐Nuremberg Henkestrasse 42, 91054 Erlangen, Germany, Fax: +49‐9131‐85‐26865
| | - Alexandru Zamfir
- Department of Chemistry and Pharmacy Chair of Organic Chemistry I University of Erlangen‐Nuremberg Henkestrasse 42, 91054 Erlangen, Germany, Fax: +49‐9131‐85‐26865
| | - Matthias Freund
- Department of Chemistry and Pharmacy Chair of Organic Chemistry I University of Erlangen‐Nuremberg Henkestrasse 42, 91054 Erlangen, Germany, Fax: +49‐9131‐85‐26865
| | - Svetlana B. Tsogoeva
- Department of Chemistry and Pharmacy Chair of Organic Chemistry I University of Erlangen‐Nuremberg Henkestrasse 42, 91054 Erlangen, Germany, Fax: +49‐9131‐85‐26865
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45
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Chen J, Captain B, Takenaka N. Helical Chiral 2,2′-Bipyridine N- Monoxides as Catalysts in the Enantioselective Propargylation of Aldehydes with Allenyltrichlorosilane. Org Lett 2011; 13:1654-7. [DOI: 10.1021/ol200102c] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jinshui Chen
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, United States
| | - Burjor Captain
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, United States
| | - Norito Takenaka
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, United States
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46
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Sulfoxides in the allylation of aldehydes in the presence of silicon tetrachloride and allyltributylstannane. OPEN CHEM 2010. [DOI: 10.2478/s11532-010-0099-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractSiCl4 can be conveniently activated by catalytic amounts of dimethyl sulfoxide or other readily-available sulfoxides for the allylation of aromatic, hetero-aromatic and unsaturated aldehydes in the presence of allyltributyl stannane. Chiral aryl methyl sulfoxides have been used to develop asymmetric allylation methods, as well as probe the aldehyde substrate scope.
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47
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Denmark SE, Williams BJ, Eklov BM, Pham SM, Beutner GL. Design, validation, and implementation of a rapid-injection NMR system. J Org Chem 2010; 75:5558-72. [PMID: 20672809 DOI: 10.1021/jo100837a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Rapid Injection NMR (RINMR) apparatus has been designed and constructed to allow the observation of fast chemical reactions in real time by NMR spectroscopy. The instrument was designed to allow the rapid (<2 s) injection and mixing of a metered volume of a reagent into a spinning NMR tube followed by rapid acquisition of the data resulting from the evolution of the chemical process. The various design criteria for this universal system included the ability to deliver any chemical reagent at any temperature and allow for the observation of any nucleus. The various challenges associated with the construction and implementation of this instrument are documented along with the validation of the accuracy of the apparatus with respect to volume and temperature. Finally, the ultimate validation and reproducibility of the technique is presented in the form of three case studies that used the instrument to elucidate various aspects of organic reaction mechanisms. The authors urge interested parties to not embark on the construction of their own instrument and invite those whose research problems might be amenable to this kind of analysis to contact the corresponding author for access to the apparatus described herein.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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48
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Choquette KA, Sadasivam DV, Flowers RA. Uncovering the mechanistic role of HMPA in the samarium Barbier reaction. J Am Chem Soc 2010; 132:17396-8. [PMID: 21090625 DOI: 10.1021/ja1088925] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The presence of HMPA is critical for the selective coupling of alkyl halides and ketones by SmI2. Although previous rate studies have shown that HMPA dramatically accelerates the reduction of alkyl halides over ketones, the basis of this rate acceleration is unknown. In this communication, we report experimental and computational evidence that demonstrate that the selectivity observed in the samarium Barbier reaction is in part a result of activation of the alkyl halide bond by HMPA.
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49
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Denmark SE, Kalyani D, Collins WR. Preparative and mechanistic studies toward the rational development of catalytic, enantioselective selenoetherification reactions. J Am Chem Soc 2010; 132:15752-65. [PMID: 20961070 PMCID: PMC2981442 DOI: 10.1021/ja106837b] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Brønsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1'-binaphthalene-2,2'-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States.
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50
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N-silyl oxyketene imines are underused yet highly versatile reagents for catalytic asymmetric synthesis. Nat Chem 2010; 2:937-43. [DOI: 10.1038/nchem.857] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 08/19/2010] [Indexed: 11/09/2022]
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