Ciclos de mejora docente en la asignatura de Química General basados en el trabajo guiado

En esta comunicación se presentan una estrategia de mejora docente progresiva basada en los denominados Ciclos de Mejora Docente, los cuales se han realizado en una parte del temario de la asignatura “Química General” del Grado en Química. Estos ciclos de mejora contemplan una reflexión sobre el modelo metodológico empleado, los contenidos fundamentales, la descripción de las distintas actividades realizadas, así como los resultados conseguidos tras la implantación de esta nueva forma de enseñanza, basada en un trabajo guiado a través de fichas docentes. Esta forma de enseñanza implica que el alumno vaya completando dichas fichas, manteniendo un razonamiento crítico a lo largo de todo el proceso de enseñanza-aprendizaje y descubriendo concepto a concepto todo lo necesario hasta llegar a alcanzar los objetivos. Para que esta forma de aprendizaje tenga éxito se requiere de un grado de compromiso alto y de una participación activa por parte del alumnado, ya que el conocimiento lo adquirirán a través de su propio trabajo, aunque éste sea guiado por el profesor. Para planificar y abordar esta idea se recurrirá inicialmente a la realización del mapa de los contenidos prioritarios del tema, al desarrollo de las actividades, a la resolución de preguntas/problemas mediante debates en clase, así como al análisis e interpretación de los resultados obtenidos tras el ciclo de mejora

Aprendizaje basado en problemas para la enseñanza de la química en la universidad

El objetivo del trabajo es analizar la eficacia de la metodología del aprendizaje basado en problemas (ABP) en una titulación del grupo de las STEM, en concreto en tres asignaturas de 1º, 2º y 3º del Grado en Química de la Universidad de Sevilla. Las clases se convierten para los estudiantes en un lugar de trabajo en grupo en el que deben resolver una serie de cuestiones concatenadas entre sí y que van progresando de menor a mayor complejidad a lo largo de los temas. Para resolver dichas cuestiones deben antes comprender los nuevos conceptos teóricos empleando para ello la bibliografía recomendada por el profesor y las opciones disponibles en internet. Al final de cada tema los alumnos comparan sus resultados con los del profesor y tienen que realizar, de manera individual, una reflexión acerca de sus errores, aciertos, incomprensiones, etc. Los resultados obtenidos al finalizar el curso correspondiente ponen de manifiesto una mejora de los resultados académicos en todas esas asignaturas, una reducción del tiempo de trabajo y un incremento significativo en el grado de satisfacción del alumnado

Synthesis of IAN-type N,N-Ligands via Dynamic Kinetic Asymmetric Buchwald-Hartwig Amination

The Pd-catalyzed coupling of racemic heterobiaryl bromides, triflates, or nonaflates with aryl/alkyl primary amines using QUINAP as the ligand provides the corresponding axially chiral heterobiaryl amines with excellent yields and enantioselectivities. Reactivity and structural studies of neutral and cationic oxidative addition intermediates support a dynamic kinetic asymmetric amination mechanism based on the labilization of the stereogenic axis in the latter and suggest that coordination of the amine to the Pd center is the stereodetermining step.Ministerio de Ciencia e Innovación CTQ2013-48164-C2-1-P, CTQ2013-48164-C2-2-P, RYC-2013-12585 for A.R.European FEDER FundsJunta de Andalucía 2012/FQM 1078

Dynamic Kinetic Resolution of Hetero biaryl Ketones by Zinc- Catalyzed Asymmetr ic Hydrosil ylation

Adiastereo- and highly enantioselective dynamic kinetic resolution (DKR) of configurationally labile hetero- biaryl ketones is described. The DKR proceeds by zinc- catalyze dhydrosilylation of the carbonyl group ,thus leading to secondary alcohols bearing axial and central chirality .The strategy relies on the labilization of the stereogenic axis that takes place thanks to aLewis acid–base interaction between anitrogen atom in the heterocycle and the ketone carbonyl group .The synthetic utility of the methodology is demonstrated through stereospecific transformations into either N,N-ligands or appealing axially chiral, bifunctional thiourea organocata- lysts.Ministerio de Ciencia e Innovación (Grants CTQ2016-76908-C2-1-P, CTQ2016-76908-C2-2-P, contract RYC-2013-12585)European FEDER FundsJunta de Andalucía (Grant 2012/FQM 10787)European Union - Marie Skłodowska-Curie (COFUND—Grant Agreement n 8 8 291780

Synthesis of IAN-type N,N-Ligands via Dynamic Kinetic Asymmetric Buchwald-Hartwig Amination

The Pd-catalyzed coupling of racemic heterobiaryl bromides, triflates, or nonaflates with aryl/alkyl primary amines using QUINAP as the ligand provides the corresponding axially chiral heterobiaryl amines with excellent yields and enantioselectivities. Reactivity and structural studies of neutral and cationic oxidative addition intermediates support a dynamic kinetic asymmetric amination mechanism based on the labilization of the stereogenic axis in the latter and suggest that coordination of the amine to the Pd center is the stereodetermining step.Peer Reviewe

A Dynamic Kinetic Asymmetric Heck Reaction for the Simultaneous Generation of Central and Axial Chirality

A highly diastereo- and enantioselective, scalable Pd-catalyzed dynamic kinetic asymmetric Heck reaction of heterobiaryl sulfonates with electron-rich olefins is described. The coupling of 2,3-dihydrofuran or N-boc protected 2,3-dihydropyrrole with a variety of quinoline, quinazoline, phthalazine, and picoline derivatives takes place with simultaneous installation of central and axial chirality, reaching excellent diastereo- and enantiomeric excesses when in situ formed [Pd0/DM-BINAP] was used as the catalyst, with loadings reduced down to 2 mol % in large scale reactions. The coupling of acyclic, electron-rich alkenes can also be performed using a [Pd0/Josiphos ligand] to obtain axially chiral heterobiaryl α-substituted alkenes in high yields and enantioselectivities. Products from Boc-protected 2,3-dihydropyrrole can be easily transformed into N,N ligands or appealing axially chiral, bifunctional proline-type organocatalysts. Computational studies suggest that a β-hydride elimination is the stereocontrolling step, in agreement with the observed stereochemical outcome of the reaction.Ministerio de Ciencia e Innovación (Grants CTQ2016-76908-C2-1-P; CTQ2016-76908-C2-2-P; CTQ2016-78083-P; RYC-2013-12585)European Commission (FEDER Programme)Junta de Andalucía (Grant 2012/FQM 10787)Universidad de Sevilla (Grant No. 1800511201)European Union - Marie Skłodowska-Curie (COFUND—Grant Agreement nº 291780

Chirality and catalysis with aromatic N-fused heterobicyclic carbenes

The benzoannulation of the most common families of aromatic NHCs, imidazol-2-ylidenes and 1,2,4-triazol-3-ylidenes, results in heterobicyclic imidazo[1,5-a]pyridin-3-ylidenes (ImPy's) and [1,2,4]triazolo[4,3-a]pyridin-3-ylidenes (TriPy's), characterized by a bridged N atom. These are versatile platforms that offer multiple possibilities for the modulation of the steric and electronic properties of the carbene ligand and/or organocatalyst, and offer also diverse opportunities for the introduction of several types of chiralities. In this paper the different families of chiral ImPy and TriPy carbenes and their application in asymmetric catalysis will be discussed.España, Ministerio de Economía y Competitividad (CTQ2013-48164-C2-1-P, CTQ2013- 48164-C2-2-P, and predoctoral fellowship to C. I.),España Junta de Andalucía (Grant 2012/FQM 1078

A Cationic Unsaturated Platinum(II) Complex that Promotes the Tautomerization of Acetylene to Vinylidene

Complex [PtMe(PMeAr)] (1), which contains a tethered terphenyl phosphine (Ar =2,6-(2,6-PrCH)CH), reacts with [H(EtO)]BAr (BAr =B[3,5-(CF)CH] ) to give the solvent (S) complex [PtMe(S)(PMeAr)] (2⋅S). Although the solvent molecule is easily displaced by a Lewis base (e.g., CO or CH) to afford the corresponding adducts, treatment of 2⋅S with CH yielded instead the allyl complex [Pt(η-CH)(PMeAr)] (6) via the alkyne intermediate [PtMe(η-CH)(PMeAr )] (5). Deuteration experiments with CD, and kinetic and theoretical investigations demonstrated that the conversion of 5 into 6 involves a Pt-promoted HC≡CH to :C=CH tautomerization in preference over acetylene migratory insertion into the Pt−Me bond.Fondos FEDER, Subprogramas Ramón y Cajal and Juan de la Cierva BES - 2011 - 048035Ministerio de Ciencia e Innovación CTQ2013 - 42501- P, CTQ2014 -51912 - REDC, CTQ - 2014 - 52769 - C3 - 3 - RJunta de Andalucía FQM - 119 and project P09 - FQM - 4832 and FQM - 212

Pyridine–hydrazone ligands in enantioselective palladium-catalyzed Suzuki–Miyaura cross-couplings

The geometries and coordination properties of modular pyridineehydrazone N,N-ligands containing C2- symmetric trans-2,5-diphenylpyrrolidine and trans-2,5-diphenylpiperidine as the terminal dialkylamino units have been analyzed by X-ray diffraction analysis of [PdCl2(N,N)] complexes [(N,N)¼pyridine hy- drazone ligand]. In combination with Pd(OAc)2 as the precatalyst, these ligands provide high enantio- selectivities (up to 95:5 er) in asymmetric SuzukieMiyaura cross couplings of 2-methoxy-1-naphthyl bromides with 1-naphthyl and 2-tolyl boronic acids.Ministerio de Economía y Competitividad TQ2013-48164-C2-1-P, CTQ2013- 48164-C2-2-P, CTQ2014-51912-REDC, RYC-2013-12585Junta de Andalucía 2012/FQM 107