1
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Pérez-Barcia Á, Peña-Gallego Á, Mandado M. Tracking the Transition from Pericyclic to Pseudopericyclic Reaction Mechanisms Using Multicenter Electron Delocalization Analysis: The [1,3] Sigmatropic Rearrangement. J Phys Chem A 2021; 125:8337-8344. [PMID: 34510896 PMCID: PMC8693182 DOI: 10.1021/acs.jpca.1c06620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Herein,
the power of multicenter electron delocalization analysis
to elucidate the intricacies of concerted reaction mechanisms is brought
to light by tracking the transition of [1,3] sigmatropic rearrangements
from the high-barrier pericyclic mechanism in 1-butene to the barrierless
pseudopericyclic mechanism in 1,2-diamino-1-nitrosooxyethane. This
transition has been progressively achieved by substituting the migrating
group, changing the donor and acceptor atoms, and functionalizing
the alkene unit with weak and strong electron-donating and electron-withdrawing
groups. Fourteen [1,3] sigmatropic reactions with electronic energy
barriers ranging from 1 to 89 kcal/mol have been investigated. A very
good correlation has been found between the barrier and the four-center
electron delocalization at the transition state, the latter calculated
for the atoms involved in the four-centered ring adduct formed along
the reaction path. Surprisingly, the barrier has been found to be
independent of the bond strength between the migrating group and the
donor atom so that only the changes induced in the multicenter bonding
control the kinetics of the reaction. Additional insights into the
effect of atom substitution and group functionalization have also
been extracted from the analysis of the multicenter electron delocalization
profiles along the reaction path and qualitatively supported by the
topological analysis of the electron density.
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Affiliation(s)
- Álvaro Pérez-Barcia
- Department of Physical Chemistry, University of Vigo, Lagoas-Marcosende s/n, 36310 Vigo, Spain
| | - Ángeles Peña-Gallego
- Department of Physical Chemistry, University of Vigo, Lagoas-Marcosende s/n, 36310 Vigo, Spain
| | - Marcos Mandado
- Department of Physical Chemistry, University of Vigo, Lagoas-Marcosende s/n, 36310 Vigo, Spain
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2
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Said AI, El-Emary TI. Diastereoselective synthesis of atropisomeric pyrazolyl pyrrolo[3,4- d]isoxazolidines via pyrazolyl nitrone cycloaddition to facially divergent maleimides: intensive NMR and DFT studies. RSC Adv 2020; 10:845-850. [PMID: 35494462 PMCID: PMC9047523 DOI: 10.1039/c9ra10039c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 12/16/2019] [Indexed: 11/21/2022] Open
Abstract
A pyrazolyl nitrone (2) underwent 1,3-dipolar cycloadditions to afford some N-substituted maleimides (3a-o). An atropisomeric character was introduced into the formed cycloadducts by using maleimides that have a restricted rotation around the C-N bond. Also, facial selectivity of both endo and exo cycloaddition was observed where the major atropisomer was one that is formed by attacking the nitrone from the less hindered face of the dipolarophile. On the other hand, maleimides with free rotation around the C-N bond led to endo and exo cycloadducts without atropisomerism. The presence of atropisomerism in the formed cycloadducts was confirmed by extensive NMR studies and DFT calculations.
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Affiliation(s)
- Awad I Said
- Chemistry Department, Faculty of Science, Assiut University Assiut Egypt 71516 +20-1012991716
| | - Talaat I El-Emary
- Chemistry Department, Faculty of Science, Assiut University Assiut Egypt 71516 +20-1012991716
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3
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Pedrón M, Delso I, Tejero T, Merino P. Concerted Albeit Not Pericyclic Cycloadditions: Understanding the Mechanism of the (4+3) Cycloaddition between Nitrones and 1,2‐Diaza‐1,3‐dienes. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Manuel Pedrón
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI). Universidad de Zaragoza 50009 Zaragoza Spain
| | - Ignacio Delso
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH). Universidad de Zaragoza‐CSIC 50009 Zaragoza Spain
| | - Tomás Tejero
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH). Universidad de Zaragoza‐CSIC 50009 Zaragoza Spain
| | - Pedro Merino
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI). Universidad de Zaragoza 50009 Zaragoza Spain
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4
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Juste-Navarro V, Prieto L, Delso I, Manzano R, Tejero T, Reyes E, Vicario JL, Merino P. A Case Study of Thiourea-Assisted Iminium Formation by Hydroxyl Anion Binding: Kinetic, Spectroscopic and Computational Evidences. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Veronica Juste-Navarro
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza-CSIC; 5009 Zaragoza Spain
| | - Liher Prieto
- Department of Organic Chemistry II; University of the Basque Country (UPV/EHU); P.O. Box 644 48080 Bilbao Spain
| | - Ignacio Delso
- Servicio de RMN, Centro de Química y Materiales de Aragón; Universidad de Zaragoza-CSIC; 5009 Zaragoza Spain
| | - Rubén Manzano
- Department of Organic Chemistry II; University of the Basque Country (UPV/EHU); P.O. Box 644 48080 Bilbao Spain
| | - Tomas Tejero
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza-CSIC; 5009 Zaragoza Spain
| | - Efraim Reyes
- Department of Organic Chemistry II; University of the Basque Country (UPV/EHU); P.O. Box 644 48080 Bilbao Spain
| | - Jose L. Vicario
- Department of Organic Chemistry II; University of the Basque Country (UPV/EHU); P.O. Box 644 48080 Bilbao Spain
| | - Pedro Merino
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI); Universidad de Zaragoza-CSIC; 5009 Zaragoza Spain
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5
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Zuo A, Birney DM. A Computational Study on the Addition of HONO to Alkynes toward the Synthesis of Isoxazoles; a Bifurcation, Pseudopericyclic Pathways and a Barrierless Reaction on the Potential Energy Surface. J Org Chem 2017; 82:8873-8881. [PMID: 28726408 DOI: 10.1021/acs.joc.7b01152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homopropargyl alcohols react with t-BuONO to form acyloximes which can be oxidatively cyclized to yield ioxazoles. The mechanism for the initial reaction of HONO with alkynes to form acyloximes (e.g., 13c) has been explored at the B3LYP/6-31G(d,p) + ZPVE level of theory. The observed chemoselectivity and regioselectivity are explained via an acid-catalyzed mechanism. Furthermore, the potential energy surface revealed numerous surprising features. The addition of HONO (8) to protonated 1-phenylpropyne (18) is calculated to follow a reaction pathway involving sequential transition states (TS6 and TS8), for which reaction dynamics likely play a role. This reaction pathway can bypass the expected addition product 21 as well as transition state TS8, directly forming the rearranged product 23. Nevertheless, TS8 is key to understanding the potential energy surface; there is a low barrier for the pseudopericylic [1,3]-NO shift, calculated to be only 8.4 kcal/mol above 21. This places TS8 well below TS6, making the valley-ridge inflection point (VRI or bifurcation) and direct formation of 23 possible. The final tautomerization step to the acyloxime can be considered to be a [1,5]-proton shift. However, the rearrangement in the case of 17h to 13c is calculated to be barrierless, arguably because the pathway is pseudopericyclic and exothermic.
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Affiliation(s)
- Ang Zuo
- Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States
| | - David M Birney
- Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States
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6
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Zhan G, Shi ML, Lin WJ, Ouyang Q, Du W, Chen YC. Direct Asymmetric Aza-Vinylogous-Type Michael Additions of Nitrones from Isatins to Nitroalkenes. Chemistry 2017; 23:6286-6289. [PMID: 28337796 DOI: 10.1002/chem.201701290] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Gu Zhan
- Department of Medicinal Chemistry; West China School of Pharmacy; Sichuan University; Chengdu 610041 P. R. China
| | - Ming-Lin Shi
- Department of Medicinal Chemistry; West China School of Pharmacy; Sichuan University; Chengdu 610041 P. R. China
| | - Wei-Jia Lin
- Department of Medicinal Chemistry; West China School of Pharmacy; Sichuan University; Chengdu 610041 P. R. China
| | - Qin Ouyang
- College of Pharmacy; Third Military Medical University; Chongqing 400038 P. R. China
| | - Wei Du
- Department of Medicinal Chemistry; West China School of Pharmacy; Sichuan University; Chengdu 610041 P. R. China
| | - Ying-Chun Chen
- Department of Medicinal Chemistry; West China School of Pharmacy; Sichuan University; Chengdu 610041 P. R. China
- College of Pharmacy; Third Military Medical University; Chongqing 400038 P. R. China
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7
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Merino P, Tejero T, Delso I, Matute R. New mechanistic interpretations for nitrone reactivity. Org Biomol Chem 2017; 15:3364-3375. [DOI: 10.1039/c7ob00429j] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of nitrones in cycloadditions and related reactions is revisited by introducing a topological perspective.
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Affiliation(s)
- Pedro Merino
- Instituto de Biocomputación y Fisica de Sistemas Complejos (BIFI)
- Universidad de Zaragoza
- 50009 Zaragoza
- Spain
| | - Tomás Tejero
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
- 50009 Zaragoza
- Spain
| | - Ignacio Delso
- Servicio de Resonancia Magnética Nuclear
- CEQMA
- Universidad de Zaragoza
- CSIC
- 50009 Zaragoza
| | - Rosa Matute
- Departamento de Ingeniería Química y Tecnologías del Medio Ambiente
- EINA
- Edificio Torres Quevedo
- 50014 Zaragoza
- Spain
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8
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Chen YR, Zhan G, Du W, Chen YC. Regioselective Asymmetric Formal (3+2) Cycloadditions of Nitrone Ylides from Isatins and Enals. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600805] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yu-Rong Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education; West China School of Pharmacy; Sichuan University; Chengdu 610041 People's Republic of China
| | - Gu Zhan
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education; West China School of Pharmacy; Sichuan University; Chengdu 610041 People's Republic of China
| | - Wei Du
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education; West China School of Pharmacy; Sichuan University; Chengdu 610041 People's Republic of China
| | - Ying-Chun Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education; West China School of Pharmacy; Sichuan University; Chengdu 610041 People's Republic of China
- College of Pharmacy; Third Military Medical University; Shapingba Chongqing 400038 People's Republic of China
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9
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Juste-Navarro V, Delso I, Tejero T, Merino P. Azomethine Ylides from Nitrones: Using Catalytic n
BuLi for the Totally Stereoselective Synthesis of trans
-2-Alkyl-3-oxazolines. Chemistry 2016; 22:11527-32. [DOI: 10.1002/chem.201602159] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Veronica Juste-Navarro
- Departamento de Síntesis y Estructura de Biomoléculas; Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza, CSIC; 50009 Zaragoza Aragón Spain
| | - Ignacio Delso
- Servicio de Resonancia Magnética Nuclear; Centro de Química y Materiales de Aragón (CEQMA); Universidad de Zaragoza, CSIC; Campus San Francisco 50009 Zaragoza Spain
| | - Tomás Tejero
- Departamento de Síntesis y Estructura de Biomoléculas; Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza, CSIC; 50009 Zaragoza Aragón Spain
| | - Pedro Merino
- Departamento de Síntesis y Estructura de Biomoléculas; Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza, CSIC; 50009 Zaragoza Aragón Spain
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10
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Roca-López D, Darù A, Tejero T, Merino P. Revisiting oxime–nitrone tautomerism. Evidence of nitrone tautomer participation in oxime nucleophilic addition reactions. RSC Adv 2016. [DOI: 10.1039/c6ra02638a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oxime–nitrone tautomerism takes place through a biomolecular mechanism. Participation of nitrone tautomer in nucleophilic addition reactions is evidenced by the first time.
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Affiliation(s)
- David Roca-López
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Andrea Darù
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Tomás Tejero
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Pedro Merino
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
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11
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García-Rodríguez J, González J, Santamaría J, Suárez-Sobrino ÁL, Rodríguez MA. Higher-order cyclization reactions of alkenyl Fischer carbene complexes: a new selective all-carbon [8 + 2] cyclization with 8-methoxyheptafulvene and computational mechanistic analysis. Dalton Trans 2016; 45:11353-61. [DOI: 10.1039/c6dt01465h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new all-carbon [8 +2] cycloaddition of alkenyl Fischer carbene complexes is described.
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Affiliation(s)
- Jaime García-Rodríguez
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Jairo González
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Javier Santamaría
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Ángel L. Suárez-Sobrino
- Instituto Universitario de Química Organometálica “Enrique Moles” and Departamento de Química Orgánica e Inorgánica
- Universidad de Oviedo
- 33071 Oviedo
- Spain
| | - Miguel A. Rodríguez
- Departamento de Química
- Centro de Investigación en Síntesis Química
- Universidad de la Rioja
- 26006 Logroño
- Spain
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12
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Darù A, Roca-López D, Tejero T, Merino P. Revealing Stepwise Mechanisms in Dipolar Cycloaddition Reactions: Computational Study of the Reaction between Nitrones and Isocyanates. J Org Chem 2015; 81:673-80. [PMID: 26682934 DOI: 10.1021/acs.joc.5b02645] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism of cycloaddition reactions of nitrones with isocyanates has been studied using density functional theory (DFT) methods at the M06-2X/cc-pVTZ level of theory. The exploration of the potential energy surfaces associated with two reactive channels leading to 1,2,4-oxadiazolidin-5-ones and 1,4,2-dioxazolidines revealed that the cycloaddition reaction takes place through a concerted mechanism in gas phase and in apolar solvents but a stepwise mechanism in polar solvents. In stepwise mechanisms, the first step of the reaction is a rare case in which the nitrone oxygen acts as a nucleophile by attacking the central carbon atom of the isocyanate (interacting with the π-system of the C═O bond) to give an intermediate. The corresponding transition structure is stabilized by an attractive electrostatic interaction favored in a polar medium. The second step of the reaction is the rate-limiting one in which the formation of 1,2,4-oxadiazolidin-5-ones or 1,4,2-dioxazolidines is decided. Calculations indicate that formation of 1,2,4-oxadiazolidin-5-ones is favored both kinetically and thermodynamically independently of the solvent, in agreement with experimental observations. Noncovalent interactions (NCI) and topological analysis of the gradient field of electron localization function (ELF) bonding confirmed the observed interactions.
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Affiliation(s)
- Andrea Darù
- Laboratorio de Síntesis Asimétrica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Aragón, Spain
| | - David Roca-López
- Laboratorio de Síntesis Asimétrica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Aragón, Spain
| | - Tomás Tejero
- Laboratorio de Síntesis Asimétrica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Aragón, Spain
| | - Pedro Merino
- Laboratorio de Síntesis Asimétrica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Aragón, Spain
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13
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Roca-López D, Polo V, Tejero T, Merino P. Mechanism Switch in Mannich-Type Reactions: ELF and NCI Topological Analyses of the Reaction between Nitrones and Lithium Enolates. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500447] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Radhamani S, Natarajan R, Unnikrishnan PA, Prathapan S, Rappai JP. Diverse reactivity of nitrones towards electron deficient acetylenes. NEW J CHEM 2015. [DOI: 10.1039/c5nj00742a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report indirect evidence for the non-concerted nature of 1,3-dipolar addition reaction between N-arylnitrones and electron deficient acetylenes.
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Affiliation(s)
- Sandhya Radhamani
- Department of Applied Chemistry
- Cochin University of Science and Technology
- Kochi – 682022
- India
| | - Rakesh Natarajan
- Department of Applied Chemistry
- Cochin University of Science and Technology
- Kochi – 682022
- India
| | | | - Sreedharan Prathapan
- Department of Applied Chemistry
- Cochin University of Science and Technology
- Kochi – 682022
- India
| | - John P. Rappai
- Department of Chemistry
- Government Victoria College
- Palakkad – 678001
- India
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15
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Majer R, Konechnaya O, Delso I, Tejero T, Attanasi OA, Santeusanio S, Merino P. Highly diastereoselective 1,3-dipolar cycloadditions of chiral non-racemic nitrones to 1,2-diaza-1,3-dienes: an experimental and computational investigation. Org Biomol Chem 2014; 12:8888-901. [DOI: 10.1039/c4ob01371a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Asymmetric 1,3-dipolar cycloadditions between 1,2-diaza-1,3-dienes and chiral non-racemic nitrones to give 3-substituted-5-diazenyl isoxazolidines were studied.
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Affiliation(s)
- Roberta Majer
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Olga Konechnaya
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Ignacio Delso
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Tomas Tejero
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
| | - Orazio A. Attanasi
- Dipartimento di Scienze Biomolecolare Sezione di Chimica Organica e dei Composti Organici Naturali
- Universitá degli Studi di Urbino “Carlo Bo”
- 61029 Urbino, Italy
| | - Stefania Santeusanio
- Dipartimento di Scienze Biomolecolare Sezione di Chimica Organica e dei Composti Organici Naturali
- Universitá degli Studi di Urbino “Carlo Bo”
- 61029 Urbino, Italy
| | - Pedro Merino
- Laboratorio de Síntesis Asimétrica
- Departamento de Síntesis y Estructura de Biomoléculas
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)
- Universidad de Zaragoza
- CSIC
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