P-Stereogenic Intermediates and MaxPHOX ligands. Iridium Catalyzed Asymmetric Hydrogenations
Asymmetric hydrogenation of double bonds by means of organometallic catalysis is a powerful tool for organic synthesis; it is an efficient and simple method to produce valued chiral compounds. Among the many different existing ligands, phosphorous ones have proven very useful for these procedures. T...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/663829 |
| Acceso en línea: | http://hdl.handle.net/10803/663829 |
| Access Level: | acceso abierto |
| Palabra clave: | Fòsfor Fósforo Phosphorus Lligands (Bioquímica) Ligandos (Bioquímica) Ligands (Biochemistry) Catalitzadors Catalizadores Catalysts Catàlisi asimètrica Catálisis asimétrica Enantioselective catalysis Hidrogenació Hidrogenación Hydrogenation Ciències Experimentals i Matemàtiques 547 |
| Sumario: | Asymmetric hydrogenation of double bonds by means of organometallic catalysis is a powerful tool for organic synthesis; it is an efficient and simple method to produce valued chiral compounds. Among the many different existing ligands, phosphorous ones have proven very useful for these procedures. The ligand plays a vital role in the catalysis, as the ligand’s chirality can transferred to the product. There is a wide range of P-based chiral ligands and can be classified in 3 groups depending on where the chirality lies; on the P unit, on the C-backbone or on both the P unit and the C-backbone. In the first section of the present PhD thesis we have studied new methodologies for the synthesis of compounds with chiral phosphorous. We developed the reduction of an important chiral phosphinous acid developed in our group to the corresponding secondary phosphine borane by means of a completely enantioselective SN2@P. This phosphine is a known compound, useful to access important P-stereogenic ligands. We have also designed a derivative of the aforementioned phosphinous acid, which is much more stable. This derivative maintains all the reactivity of the phosphinous acid in the SN2@P reaction with nucleophiles. In the second section of the present PhD thesis we were able to produce a small family of P-stereogenic Ir-MaxPHOX catalysts. We have applied this library to the reduction of different interesting substrates from a pharmaceutical or agrochemical point of view. We hydrogenated different challenging imines (N-aryl imines and N-alkyl imines) to the corresponding amines with excellent enantioselectivities. We also reduced cyclic enamides (α- and β-enamides) to the corresponding amides. In this later case, the control over the ee was complete. These are the best results reported in the literature so far. |
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