Activación de aldehídos a,b-insaturados mediante aminocatálisis en procesos enantioselectivos. Cicloadiciones (3+2) y reacciones en cascada Michael/Henry
- Autores: Naiara Fernández Hernández
- Directores de la Tesis: María Luisa Carrillo Fernández (dir. tes.), José Luis Vicario Hernando (dir. tes.)
- Lectura: En la Universidad del País Vasco - Euskal Herriko Unibertsitatea ( España ) en 2012
- Idioma: español
- Tribunal Calificador de la Tesis: Miguel Yus Astiz (presid.), Olga García Mancheño (secret.), Maria Esther Lete Exposito (voc.), Anna Roglans i Ribas (voc.), Gonzalo Blay Llinares (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: ADDI
- Resumen
During the research that it is summarized in the present memory, the activation of enals via iminium ion catalysis in different transformations has been studied. Firstly, a 1,3-dipolar cycloaddition between stable azomethine ylides and a,b-unsaturated aldehydes catalyzed by a chiral imidazolidinone derivative has been optimized. Employing this methodology we have synthesized a large range of densely substituted pyrroloisoquinolines and pyrrolophthalazines with good yields and high values of diastereo- and enantioselectivity. Moreover, a mechanistic study has been carried out based on DFT calculations and experimental data which have allowed us to propose that the (3+2) cycloaddition reaction follows a sequential Michael addition/Mannich cyclization pathway. The formation of the iminium ion as a result of the condensation between the a,b-unsaturated aldehyde and the catalyst plays an essential role, regarding both reactivity and stereoselectivity. On the other hand we have developed a methodology to carry out a cascade Michael/Henry reaction followed by a sequential dehydration. Starting from simple substrates (2-nitromethylacrilates and a,b-unsaturated aldehydes) and employing a prolinol-derivative catalyst a series of quiral nitrocyclohexadienes have been synthesized.
