Reflexiones sobre el concepto de política

This short article aims to reflect on the definition of the term politics in general. To do this, after applying the scientific method and structuring a short work on the problem, a solution model is used and a form of hypothesis development is tested in different social fields. It concludes with the inference of a generic concept of proven policy through the proposed model.Este breve artículo tiene el objetivo de reflexionar sobre la definición del término política en general.Para ello luego de aplicar el método científico y estructurar un trabajo corto sobre la problemática, se utiliza un modelo de solución y se prueba una forma de desarrollo de hipótesis en diferentes campos sociales. Se concluye con la inferencia de un concepto genérico de política probado a través del modelo propuesto

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

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

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)

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

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

Radical Cyclization of Epoxy Vinyl- and Allylsulfones Promoted by Titanocene Chloride

[EN]A titanocene-mediated intramolecular radical addition of different epoxy vinyl- and allylsulfones has been achieved. Five- and six-membered ring products were obtained in good to excellent yields in the presence of both 2.2 and 0.2 equiv of Cp2TiCl. A novel double-activation strategy allowed us to achieve small-size rings such as cyclobutanes and cyclopropanes

Radical Titanocene Promoted Coupling of Epoxides and Vinyl Sulfones

[EN]A radical coupling reaction of diverse vinyl sulfones and epoxides was mediated by Cp2TiCl (Cp = cyclopentadienyl) to provide a straightforward synthetic pathway to hydroxy sulfones. The reaction was successfully achieved by using either an excess or a catalytic amount of the TiIII reagent. The scope of the reaction was studied for several different functionalized and substituted epoxides and vinyl sulfones

Titanocene‐Promoted Eliminations on Epoxy Alcohols and Epoxy Esters

[EN]The reaction of a series of 2,3-epoxy alcohols and the corresponding formates, acetates, and benzoates promoted by Cp2TiCl has been studied. The different outcome of the reaction of epoxy derivatives has been rationalized in terms of mechanistically biased processes. After homolytic oxirane cleavage, four main types of reaction were found: dehydroxylation, decarboxylation, dehydrogenation, and deoxygenation. The reaction products varied according to the substitution pattern. The radical nature of these eliminations is demonstrated