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Synthetic applications of β-enamino esters

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Author(s):
Fernando Luiz Cardoso Pereira
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
Defense date:
Examining board members:
Helena Maria Carvalho Ferraz; Fernando Antonio Santos Coelho; Ronaldo Aloise Pilli; Helio Alexandre Stefani; Claudio Di Vitta
Advisor: Helena Maria Carvalho Ferraz
Abstract

A series of acyclic β-enamino esters was submitted to iodocyclization reactions or to iodine-mediated lactonization, leading to the corresponding cyclic iodo-β-enamino esters or β-enamino lactones. Dehydroiodination of the five-membered ring enamino esters furnished pyrrole, tetrahydroindole and hexahydroindole derivatives, under basic or neutral conditions. The six-membered ring enamino esters, when submitled to treatment with triethylamine, gave rise to trisubstituted cyclopentanes. This transformation occurred through an intramolecular nucleophilic substitution, instead of the expected dehydroiodination reaction. The effect of the N-substituent in these reactions was studied for a series for N-alkyl and N-aryl derivatives. The β-enamino lactones were obtained in poor yields, due to the poliiodination of the substrates, and showed to be resistent to reduction of the carbon-carbon double bond under several conditions. A study of conformational analysis of the bicyclic β-enamino esters was undertaken, using 1H-NMR and13C-NMR data, molecular mechanics and semi-empirical methods. From this study, it was observed that the bicyclic compounds adopt different conformations depending upon the N-substituent. (AU)