Asymmetric aminocatalysis: a modern strategy for molecules, challenges and life

Pesciaioli, Fabio (2011) Asymmetric aminocatalysis: a modern strategy for molecules, challenges and life , [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Scienze chimiche, 23 Ciclo. DOI 10.6092/unibo/amsdottorato/3786.
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Abstract

The studies conducted during my Phd thesis were focused on two different directions: 1. In one case we tried to face some long standing problems of the asymmetric aminocatalysis as the activation of encumbered carbonyl compounds and the control of the diastereoisomeric ratio in the diastero- and enantioselective construction of all carbon substituted quaternary stereocenters adjacent a tertiary one. In this section (Challenges) was described the asymmetric aziridination of ,-unsaturated ketones, the activation of ,-unsaturated -branched aldehydes and the Michael addition of oxindoles to enals and enones. For the activation via iminium ion formation of sterically demanding substrates, as ,-unsaturated ketones and ,-unsaturated -branched aldehydes, we exploited a chiral primary amine in order to overcome the problem of the iminium ion formation between the catalyst and encumbered carbonylic componds. For the control of diastereoisomeric ratio in the diastero- and enantioselective construction of all carbon substituted quaternary stereocenters adjacent a tertiary one we envisaged that a suitable strategy was the Michael addition to 3 substituted oxindoles to enals activated via LUMO-lowering catalysis. In this synthetic protocol we designed a new bifunctional catalyst with an amine moiety for activate the aldehyde and a tioureidic fragment for direct the approach of the oxindole. This part of the thesis (Challenges) could be considered pure basic research, where the solution of the synthetic problem was the goal itself of the research. 2. In the other hand (Molecules) we applied our knowledge about the carbonylic compounds activation and about cascade reaction to the synthesis of three new classes of spirooxindole in enantiopure form. The construction of libraries of these bioactive compounds represented a scientific bridge between medicinal chemistry or biology and the asymmetric catalysis.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Pesciaioli, Fabio
Supervisore
Co-supervisore
Dottorato di ricerca
Scuola di dottorato
Scienze chimiche
Ciclo
23
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
organocatalysis primary amine cascade reactions spirooxindoles asymmetric catalysis
URN:NBN
DOI
10.6092/unibo/amsdottorato/3786
Data di discussione
19 Aprile 2011
URI

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