Palladium, ruthenium and iron in intramolecular transition metal-catalyzed carbene functionalization reactions of amino-tethered α-diazoesters
Transition metal-catalyzed intramolecular C–H insertions of diazo compounds represent one of the most elegant and versatile methods in organic synthesis for the construction of carbocyclic and heterocyclic frameworks. In these reactions a C–C bond is formed with high atom economy, with N2 gas being...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/671148 |
| Acceso en línea: | http://hdl.handle.net/10803/671148 |
| Access Level: | acceso abierto |
| Palabra clave: | Química orgànica Química orgánica Organic chemistry Metalls de transició Metales de transición Transition metals Catàlisi Catálisis Catalysis Carbens Carbenos Carbenes Diazocomposts Diazocompuestos Diazo compounds Compostos heterocíclics Compuestos heterocíclicos Heterocyclic compounds Ciències Experimentals i Matemàtiques 547 |
| Sumario: | Transition metal-catalyzed intramolecular C–H insertions of diazo compounds represent one of the most elegant and versatile methods in organic synthesis for the construction of carbocyclic and heterocyclic frameworks. In these reactions a C–C bond is formed with high atom economy, with N2 gas being the only subproduct. In the last years, in the context of a research program aimed at developing efficient methodologies for the synthesis of nitrogen heterocycles, our research group has been studying the transition metal-catalyzed decomposition of amino-tethered α - diazo carbonyl compounds. Specifically, we have reported that palladium catalysts are able to promote the intramolecular carbene C–H insertions to produce pyrrolidines from α-diazoesters, and oxindoles as well as β-lactams from α -diazo- α - (methoxycarbonyl)acetamides. As a continuation of these studies, in this Thesis we first explored the use of Pd, Rh(II) and Ru(II)-based catalysts for the intramolecular carbene C(sp3)–H insertion of γ - amino-α-diazoesters leading to pyrrolidines. Our comparative study allowed us to identify differences in the reactivities and selectivities between the different transition metals. The results obtained in these annulation reactions show that, although the chemoselectivity of the process is highly substrate-dependent, it can be controlled by adequate catalyst selection. Taking this work as a reference, we then investigated the use of some structurally diverse Ru(II)-complexes to promote the C(sp3)–H insertion of γ-amino-α-diazoesters to form pyrrolidines. In this context, we have described the first examples of an unprecedented non-metathetic chemistry of Grubbs complexes, which were applied to achieve this target. Moreover, in our preliminary attempts to develop an enantioselective version of this carbene C(sp3)–H insertion reaction, we focused our attention on the use of different chiral Ru(II)-catalysts. We also investigated the synthesis of tetrahydroquinolines by transition metal- catalyzed intramolecular aromatic CAr(sp2)-H functionalization of γ -anilino α-diazoesters. Both palladium(0)- and Grubbs catalysts were explored for this purpose. Finally, we broadened our investigation on the transition metal-catalyzed decomposition of amino-tethered diazoesters by exploring the reactions of δ−amino and β-amino α-diazoesters. Some diverse palladium and ruthenium complexes as well as different iron salts were studied. |
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