Ramon Rios

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Organization: University of Southampton , England
Department: School of Chemistry
Title: Associate Professor(PhD)

TOPICS

Co-reporter:Marta Meazza, Mark E. Light, Andrea Mazzanti and Ramon Rios  
Chemical Science 2016 vol. 7(Issue 2) pp:984-988
Publication Date(Web):30 Oct 2015
DOI:10.1039/C5SC03597J
In the present paper we report our latest efforts in pushing the boundaries of synergistic catalysis. We propose the use of 3 different catalytic cycles working in concert for the formation of cis cyclopropane derivatives of benzoxazoles with excellent stereoselectivities. This is the proof of concept that synergistic catalysis could be successfully used in cascade reactions.
Co-reporter:Dr. Sun Min Kim;Young Sug Kim;Dong Wan Kim;Dr. Ramon Rios;Dr. Jung Woon Yang
Chemistry - A European Journal 2016 Volume 22( Issue 7) pp:2214-2234
Publication Date(Web):
DOI:10.1002/chem.201503960

Abstract

Stereocontrolled formation of carbon−carbon and carbon−heteroatom bonds through asymmetric organocatalysis is a formidable challenge for modern synthetic chemistry. Among the most significant contributions to this field are the transformations involving the use of acetaldehyde or α-heteroatom-substituted acetaldehydes for constructing valuable synthons (e.g., amino acid derivatives and hydroxycarbonyl). In this Minireview, versatile (enantioselective) organocatalytic transformations are discussed.

Co-reporter:Marta Meazza, Maria Ashe, Hun Yi Shin, Hye Sung Yang, Andrea Mazzanti, Jung Woon Yang, and Ramon Rios
The Journal of Organic Chemistry 2016 Volume 81(Issue 9) pp:3488-3500
Publication Date(Web):April 15, 2016
DOI:10.1021/acs.joc.5b02801
Herein, we describe the first enantioselective cyclopropanation of enals using benzyl chlorides as bifunctional (nucleophilic and electrophilic) reagents. The reaction is simply catalyzed by chiral secondary amines to afford the formyl cyclopropane derivatives in good yields with moderate to excellent stereoselectivities.
Co-reporter:Yanbin Zhang, Yong An, Jing Sun, Aishun Ding, Yu Wang, Ramon Rios, Hao Guo
Tetrahedron Letters 2015 Volume 56(Issue 46) pp:6499-6502
Publication Date(Web):18 November 2015
DOI:10.1016/j.tetlet.2015.10.012
We report herein a novel photocyclopropanation of dibromomalonates with alkenes in the presence of Hünig base. This protocol provides an environmentally benign approach for the synthesis of multisubstituted cyclopropanes, since no catalyst is required. The Photo-induced Electron Transfer (PET) from Hünig base to dibromomalonate is the key process during this transformation.We report herein a novel photocyclopropanation of dibromomalonates with alkenes in the presence of Hünig base. This protocol provides an environmentally benign approach for the synthesis of multisubstituted cyclopropanes, since no catalyst is required. The Photo-induced Electron Transfer (PET) from Hünig base to dibromomalonate is the key process during this transformation.
Co-reporter:Jan Vesely and Ramon Rios  
Chemical Society Reviews 2014 vol. 43(Issue 2) pp:611-630
Publication Date(Web):04 Nov 2013
DOI:10.1039/C3CS60321K
Nucleophilic addition to carbon–nitrogen double bonds (imines) represents one of the most common strategies for the synthesis of amine derivatives. In order to circumvent the problem associated with low reactivity of imines in nucleophilic addition, various imines with electron-withdrawing groups at nitrogen have been studied, and many of them were successfully applied in asymmetric methodologies. Especially N-carbamoyl imines were found to be useful in the enantioselective synthesis of various organic compounds, due to their increased reactivity toward nucleophiles as well as limited difficulties connected with the removal of the carbamoyl moiety in target molecules. The aim of this review is to cover enantioselective methods based on N-carbamoyl imines, focusing on synthetically useful protocols.
Co-reporter:Victor Ceban, Piotr Putaj, Marta Meazza, Mateusz B. Pitak, Simon J. Coles, Jan Vesely and Ramon Rios  
Chemical Communications 2014 vol. 50(Issue 56) pp:7447-7450
Publication Date(Web):20 May 2014
DOI:10.1039/C4CC00728J
An expedited method has been developed for the diastereoselective synthesis of highly functionalized alkyl-azaarene systems with good yields and high diastereoselectivities (>15:1 dr). The methodology includes a synergistic catalysis event involving organometallic (10 mol% AgOAc) activation of an alkyl azaarene and Lewis base (10 mol% DABCO) activation of a Morita–Baylis–Hillman carbonate. The structure and relative configuration of a representative product were confirmed by X-ray analysis.
Co-reporter:Xavier Companyó, Pierre-Yves Geant, Andrea Mazzanti, Albert Moyano, Ramon Rios
Tetrahedron 2014 70(1) pp: 75-82
Publication Date(Web):
DOI:10.1016/j.tet.2013.11.028
Co-reporter:Marta Meazza;Victor Ceban;Dr. Mateusz B. Pitak;Dr. Simon J. Coles ;Dr. Ramon Rios
Chemistry - A European Journal 2014 Volume 20( Issue 51) pp:16853-16857
Publication Date(Web):
DOI:10.1002/chem.201404565

Abstract

A novel catalytic enantioselective methodology based on synergistic catalysis is reported. The strategy involves: 1) the metal-Lewis-acid activation of alkylazaarenes, and 2) the secondary-amine activation of enals. Consequently, highly functionalized chiral alkylazaarenes were obtained in good yields and with reasonable stereoselectivity.

Co-reporter:Xavier Companyó, Andrea Mazzanti, Albert Moyano, Anna Janecka and Ramon Rios  
Chemical Communications 2013 vol. 49(Issue 12) pp:1184-1186
Publication Date(Web):19 Dec 2012
DOI:10.1039/C2CC38659C
All in one pot: an organocatalytic highly enantioselective synthesis of α-methylene-γ-lactones has been reported. The reaction between protected 2-hydroxymalonates and MBH carbonates is simply catalysed by chiral Lewis bases affording after acid treatment the corresponding lactones in excellent yields and enantioselectivities.
Co-reporter:Victor Ceban, Kane Hands, Marta Meazza, Mark E. Light, Ramon Rios
Tetrahedron Letters 2013 Volume 54(Issue 52) pp:7183-7187
Publication Date(Web):25 December 2013
DOI:10.1016/j.tetlet.2013.10.110
A new three-component cascade reaction for the synthesis of thiohydantoins is reported. The reaction between α-amino esters, nitrostyrenes, and aromatic isothiocyanates is efficiently promoted by organic bases to afford highly substituted thiohydantoins in moderate to good yields and diastereoselectivities.A new three-component cascade reaction for the synthesis of thiohydantoins is reported. The reaction between α-amino esters, nitrostyrenes, and aromatic isothiocyanates is efficiently promoted by organic bases to afford highly substituted thiohydantoins in moderate to good yields and diastereoselectivities.
Co-reporter:Aishun Ding, Yu Wang, Ramon Rios, Jing Sun, ... Hao Guo
Journal of Saudi Chemical Society (November 2015) Volume 19(Issue 6) pp:706-709
Publication Date(Web):1 November 2015
DOI:10.1016/j.jscs.2015.07.004
A new method for the photooxidation of triarylphosphines into the corresponding oxides is developed. In this new protocol, neither a catalyst nor an additive is required. The greenest oxidant, oxygen in air atmosphere, is used. After a short period of photo irradiation at rt, stoichiometric amounts of the oxides can be easily afforded by simply recycling the solvent under vacuum. No waste is formed in the whole process of this reaction. The substrate scope of this reaction is broad, showing very good application prospects in both organic chemistry and industrial processes.
Co-reporter:Jan Vesely and Ramon Rios
Chemical Society Reviews 2014 - vol. 43(Issue 2) pp:NaN630-630
Publication Date(Web):2013/11/04
DOI:10.1039/C3CS60321K
Nucleophilic addition to carbon–nitrogen double bonds (imines) represents one of the most common strategies for the synthesis of amine derivatives. In order to circumvent the problem associated with low reactivity of imines in nucleophilic addition, various imines with electron-withdrawing groups at nitrogen have been studied, and many of them were successfully applied in asymmetric methodologies. Especially N-carbamoyl imines were found to be useful in the enantioselective synthesis of various organic compounds, due to their increased reactivity toward nucleophiles as well as limited difficulties connected with the removal of the carbamoyl moiety in target molecules. The aim of this review is to cover enantioselective methods based on N-carbamoyl imines, focusing on synthetically useful protocols.
Co-reporter:Xavier Companyó, Andrea Mazzanti, Albert Moyano, Anna Janecka and Ramon Rios
Chemical Communications 2013 - vol. 49(Issue 12) pp:NaN1186-1186
Publication Date(Web):2012/12/19
DOI:10.1039/C2CC38659C
All in one pot: an organocatalytic highly enantioselective synthesis of α-methylene-γ-lactones has been reported. The reaction between protected 2-hydroxymalonates and MBH carbonates is simply catalysed by chiral Lewis bases affording after acid treatment the corresponding lactones in excellent yields and enantioselectivities.
Co-reporter:Marta Meazza, Mark E. Light, Andrea Mazzanti and Ramon Rios
Chemical Science (2010-Present) 2016 - vol. 7(Issue 2) pp:NaN988-988
Publication Date(Web):2015/10/30
DOI:10.1039/C5SC03597J
In the present paper we report our latest efforts in pushing the boundaries of synergistic catalysis. We propose the use of 3 different catalytic cycles working in concert for the formation of cis cyclopropane derivatives of benzoxazoles with excellent stereoselectivities. This is the proof of concept that synergistic catalysis could be successfully used in cascade reactions.
Co-reporter:Victor Ceban, Piotr Putaj, Marta Meazza, Mateusz B. Pitak, Simon J. Coles, Jan Vesely and Ramon Rios
Chemical Communications 2014 - vol. 50(Issue 56) pp:NaN7450-7450
Publication Date(Web):2014/05/20
DOI:10.1039/C4CC00728J
An expedited method has been developed for the diastereoselective synthesis of highly functionalized alkyl-azaarene systems with good yields and high diastereoselectivities (>15:1 dr). The methodology includes a synergistic catalysis event involving organometallic (10 mol% AgOAc) activation of an alkyl azaarene and Lewis base (10 mol% DABCO) activation of a Morita–Baylis–Hillman carbonate. The structure and relative configuration of a representative product were confirmed by X-ray analysis.
2,6-Heptadienal, (2E)-
Phosphoramidic acid, (phenylmethyl)-, diethyl ester
Phosphoramidic acid, (4-cyanophenyl)-, diethyl ester
2,4-Hexadienal, (2E)-
PHOSPHORAMIDIC ACID, (4-CHLOROPHENYL)-, DIETHYL ESTER
CYCLOPROPANECARBOXYLIC ACID, 1-CYANO-2-ETHENYL-, METHYL ESTER (9CI)
ISOQUINOLINE, 1,2,3,4-TETRAHYDRO-2-(4-METHYLPHENYL)-
Benzonitrile, 4-[(1E)-3-oxo-1-propenyl]-
5-Chloro-2-ethyl-6-nitro-1,3-benzoxazole
2-PROPENAL, 3-(2-BROMOPHENYL)-