Alajarín Cerón, Mateo

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Alajarín Cerón, Mateo

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Alajarín Cerón, Mateo

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Universidad de Murcia. Departamento de Química Orgánica

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Open Access
Intramolecular cyclization of Azido-Isocyanides triggered by the Azide Anion: an experimental and computational study
(American Chemical Society Publications, 2023-06-20) Alajarín Cerón, Mateo; Cutillas Font, Guillermo; López Leonardo, Carmen; Orenes, Raul-Angel; Marín Luna, Marta; Pastor Vivero, Aurelia; Química Orgánica
This work describes the unprecedented intramolecular cyclization occurring in a set of alfa-azido-beta-isocyanides in the presence of catalytic amounts of sodium azide. These species yield the tricyclic cyanamides [1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-carbonitriles, whereas in the presence of an excess of the same reagent, the azido-isocyanides convert into the respective C-substituted tetrazoles through a [3+2] cycloaddition between the cyano group of the intermediate cyanamides and the azide anion. The formation of tricyclic cyanamides has been examined by experimental and computational means. The computational study discloses the intermediacy of a long-lived N-cyanoamide anion, detected by NMR monitoring of the experiments, subsequently converting into the final cyanamide in the rate determining step. The chemical behavior of these azido-isocyanides endowed with an aryl-triazolyl linker, has been compared with that of a structurally identical azido-cyanide isomer, experiencing a conventional intramolecular [3+2] cycloaddition between its azido and cyanide functionalities. The synthetic procedures described herein constitute metal-free approaches to novel complex heterocyclic systems, such as [1,2,3]triazolo[1,5-a]quinoxalines and 9H-benzo[f]tetrazolo[1,5-d][1,2,3]triazolo[1,5-a][1,4]diazepines.
Open Access
A Thiourea-based Rotaxane Catalyst: Nucleophilic Fluorination Phase-Transfer Process Unlocked by the Mechanical Bond
(American Chemical Society, 2025-03-18) Martínez Cuezva, Alberto; Berná Cánovas, José; Puigcerver Alarcón, Julio; Juan S. Santiago Dato; Alajarín Cerón, Mateo; Química Orgánica
We report a five-component clipping approach using activated isophthaloyl-derived esters to synthesize an amide-based thiourea rotaxane. This method overcomes acyl chloride limitations with nucleophilic thiourea threads. The steric hindrance of the mechanical bond enables, for the first time, an interlocked thiourea as a hydrogen-bonding phase-transfer organocatalyst in nu-cleophilic fluorinations. This highlights how mechanical bonds expand thiourea catalysis to processes previously incompatible with conventional catalysts.
Open Access
Post-Synthetic Modifications of Amide-Enaminone-Based [2]Rotaxanes for the Stereocontrolled Synthesis of Functionalized β-Lactams
(Wiley, 2025-07-09) Martínez Cuezva, Alberto; Berná Cánovas, José; Alajarín Cerón, Mateo; Razi, Syed Sibtay; Pérez Artigao, Isabel Mª; Química Orgánica
Novel amido-enaminone threads serve as efficient templates for the assembly of hydrogen-bonded [2]rotaxanes, enabling versatile post-synthetic modifications. Benzyl groups on the amido moiety allow for diastereoselective intramolecular cyclizations, yielding interlocked β-lactams. The enaminone motif makes possible the stopper exchange while preserving the mechanical bond. Combining cyclization with one-pot stopper exchange and dethreading enables the stereoselective synthesis of highly functionalized non-interlocked lactams featuring a second heterocycle at their side chain via reactions with hydrazines or hydroxylamine
Open Access
Dataset used for the article: Post-Synthetic Modifications of Amide-Enaminone-Based [2]Rotaxanes for the Stereocontrolled Synthesis of Functionalized β-Lactams
(2025-10-01) Martínez Cuezva, Alberto; Berná Cánovas, José; Alajarín Cerón, Mateo; Razi, Syed Sibtay; Pérez Artigao, Isabel Mª; Química Orgánica
Open Access
2-Isocyanoanilines and their mono-Boc-protected derivatives
(Royal Society of Chemistry, 2025-07-15) Saura Sanmartín, Adrián; López Leonardo, Carmen; Alajarín Cerón, Mateo; Química Orgánica; Facultad de Química
Among the variety of synthetically useful isocyanides, 2-isocyanoanilines have been scarcely reported in the chemical literature, despite the rich chemistry that expectedly could derive from the reactivities of their two functional groups. This is the case not only for the parent compound but also for most of their N-monosubstituted derivatives. The reason behind such behavior relies upon their chemical instability, apparently attributable to the presence of the N–H bond. Among these latter species, two tert-butyl carbamates are notorious exceptions, as they have been widely utilized in multicomponent reactions but poorly described. This review covers the chemistry of these compounds from a critical perspective, analyzing the causes of the instability of these privileged molecular scaffolds, as well as highlighting the reactivity of their mono-Boc-protected derivatives.
Open Access
Heterocyclizations at the Isocyanide Carbon: Mechanistic Insights into the 2-Isocyanoaniline to Benzimidazole Conversion
(American Chemical Society, 2026-01-15) Alajarín Cerón, Mateo; Marín Luna, Marta; Química Orgánica
Benzo-fused heteroazacycles can form through spontaneous cyclizations of phenylisocyanides bearing some electron donor substituents at the ortho position. Although such reactions have been known since the 1970s, a clear mechanistic understanding of these transformations remains absent. Here, we disclose a detailed computational analysis aimed at elucidating the more plausible mechanism for one of these cyclizations, the o-isocyanoaniline to benzimidazole conversion. Our results show that a transient 1,4-diazabutatriene could play a key role in this cyclization by enabling a reaction pathway of lower barrier than the unimolecular concerted process.