Titanocene-promoted stereoselective eliminations on epoxy alcohols derived from R-(−)-carvone

[EN]The reaction of several stereoisomeric epoxy alcohols, obtained from R-(−)-carvone, and their corresponding formates, acetates, and benzoates, promoted by Cp2TiCl has been studied. The different outcomes of the reaction of epoxy derivatives are rationalized in terms of mechanistically biased processes. The radicals emerging from oxirane cleavage provide two types of reaction: dehydroxylation (deoxycarbonylation) and dehydrogenation. The results offer considerable support for the radical elimination theory of hydroxyl, formyloxyl, and acetoxyl groups. The inability of tertiary radicals to be reduced by the Ti(III) complex is demonstrated unequivocally

Radical reactions on pinene-oxide derivatives induced by Ti(III)

[EN]A practical, brief and selective synthesis of several pinene oxide derived terpenoids can be achieved from readily available starting materials. The key step is a radical reaction promoted by titanocene chloride

El acceso a los destinos rurales: una perspectiva para la planificación territorial del turismo en una región de interior (Castilla-La Mancha)

El artículo propone una tipología de áreas de mercado turístico a partir del análisis de la accesibilidad a los principales activos turísticos de Castilla-La Mancha. El objetivo es profundizar en la búsqueda de explicaciones lógicas sobre el impacto que tiene la accesibilidad en el desarrollo turístico de los territorios. Especialmente en áreas rurales donde la dotación diferencial de infraestructuras de transporte ha generado desequilibrios notables. Su comprensión, desde la lógica estructural origen-enlace-destino que adoptan muchos de los sistemas territoriales, supone un avance en el complejo proceso de planificación territorial del turismo. Los resultados obtenidos y trasladados a la escala supramunicipal ponen de relieve potencialidades y desventajas a considerar en las estrategias de los espacios rurales. 

On the Mechanism and Kinetics of Radical Reactions of Epoxyketones and Epoxynitriles Induced by Titanocene Chloride

[EN]The reactions of a series of epoxynitriles and epoxyketones induced by titanocene chloride have been studied. The kinetics of the decyanogenation of β,γ-epoxynitriles with Ti(III) corresponds to a radical reaction (k25 ≈ 106 s-1), as demonstrated by competition experiments with H-transfer from 1,4- cyclohexadiene (1,4-CHD) or PhSH or conjugate addition to acrylonitrile. The 5-exo cyclization onto nitrile induced by Ti(III) is a radical reaction (k25 ≈ 107 s-1) as seen in competition experiments with H-transfer from PhSH or the titanocene-water complex. The iminyl or alkoxyl radicals generated by 5-exo cyclization onto nitriles or ketones only undergo a reduction with Ti(III). This reaction overwhelms any alternative process, such as tandem cyclization onto alkenes or β-scission. Iminyl radicals generated by 4-exo cyclizations onto nitriles undergo reduction with Ti(III) and β-scission reaction in a ratio of 96:4 when the R-substituent is CN. Alkoxyl radicals from 4-exo cyclizations onto ketone carbonyls undergo reduction with Ti(III) and β-scission in a ratio of 60:40 when the R-substituent is COOR. In nearly all the reactions studied, the role of Ti(III) is triple: a radical initiator (homolytic cleavage of oxirane), a Lewis acid (coordination to CN or CdO), and a terminator (reduction of iminyl or alkoxyl radicals)

El concepto de cohesión territorial: escalas de aplicación, sistemas de medición y políticas derivadas

El concepto de cohesión territorial ha ido cobrando fuerza durante la última década como una de las expresiones más citadas en el ámbito temático de las políticas territoriales. Sin embargo, hasta fechas muy recientes ha adolecido de un escaso nivel de concreción, tanto teórica como práctica. Este texto se propone avanzar en dicha concreción, abordando las cuestiones clave del concepto de cohesión territorial en Europa, en cuanto a su definición; escala y ámbito de actuación; planteamiento de fórmulas para mejorar la cooperación y coordinación entre las políticas sectoriales y territoriales; o el debate, esencial para su aplicabilidad práctica, acerca del establecimiento de indicadores para la evaluación de las características y tendencias de dicha cohesión territorial. Todo ello en el contexto teórico del debate suscitado por la publicación del Libro Verde sobre la cohesión territorial, elaborado y difundido por la Comisión de las Comunidades Europeas.The concept of territorial cohesion has gained strength during the last decade as one of the most quoted in the subject area of territorial policies. However, until very recently, has suffered from a low level of detail, both theoretical and practical. This paper seeks to be another step in specifying the main territorial cohesion-related issues by addressing the key issues of the concept in Europe, in terms of its definition, the scale and scope of territorial action; the question of how to improve co-operation and co-ordination between sectorial and territorial policies as well as the type of indicators that must be developed in order to evaluate both the characteristics and trends in territorial cohesion. These and other questions are addressed in the context of the theoretical debate raised after the publication in 2008 of the Green Paper on Territorial Cohesion by the Commission of the European Communities

Synthesis of the BCDE Molecular Fragment of Azadiradione Mediated by Titanocene(III)

[EN]A practical, short, and diastereoselective synthesis of the azadiradione BCDE fragment from a readily available starting material is described. The key step was the titanocene(III)-promoted tandem cyclization of unsaturated epoxy nitrile

Reporte analítica de proyectos web con Google Analytics

Nuestro Trabajo de Fin de Grado trata sobre los conceptos clave de la analítica web 2.0. Google Analytics ha sido la herramienta principal con la que hemos enlazado los datos y las páginas webs. Después de analizar cuatro webs distintas mediante la herramienta antes mencionada hemos sacado datos relevantes para las mismas. Nuestro objetivo era profundizar un poco en la analítica web y con este trabajo lo hemos conseguido.Grado en Publicidad y Relaciones Pública

Radical reactions of epoxy esters induced by titanocene chloride

[EN]The reductive radical cyclizations of several epoxy esters have been achieved using titanocene chloride. The tether length from the initial radical to the carbonyl acceptor is the key of the reactions. We obtained products from radical cyclization onto carbonyl formate and products from formate and hydrogen elimination. The stereochemical outcome of the 5-exo radical cyclization of two diastereomers is reported. A radical cascade cyclization of an unsaturated epoxy formate is also described

Titanocene-Promoted Intermolecular Couplings of Epoxides with Nitriles. An Easy Access to β-Hydroxyketones

[EN]Radical couplings of epoxides and nitriles mediated by Cp2TiCl provide a diastereoselective route to the synthesis of β-hydroxyketones. The conditions of this “aldol-like” reaction are mild enough to avoid the dehydration of the β-hydroxyketone. The scope of the coupling reaction with functionalized and tetrasubstituted epoxides has been studied. The radical character of the coupling reactions is demonstrated