Epoxide ring opening is a frequently required transformation in Organic Synthesis. In this paper we describe the application of NbCl5 for this purpose using three different substrates. Chlorohydrins, 1,2-diols, products containing solvent residues as well as rearrangement products are obtained, depending on both the substrate structure and reaction conditions. Rationalizations to account for some of the results are suggested.
Dedico este trabalho aos meus amados pais, Dirce & Valdemar Vocês são muito importantes para mim! Ofereço ao meu querido noivo, Alexandre Aquele, escolhido por Deus, para estar ao meu lado! Agradecimentos À Deus, pelo seu infinito amor! E, por todas as bênçãos derramadas em minha vida! À toda minha família, que sempre me incentivou! Amo muito todos vocês! Aos meus pais, Dirce e Valdemar, que são grandes exemplos em minha vida. Às minhas queridas irmãs, Luciana e Cristiana, e ao meu querido irmão Paulo. À minha irmãzinha Lucimara (in memorian). À minha linda sobrinha, Amanda. Aos meus estimados cunhados, Antônio e Marcelo. Às minhas avós, Vicentina e Ana (in memorian).
A simple and efficient method for the preparation of 1-methyl-3-oxo-7-oxabicyclo[2.2.1]hept-5-en-2-carboxylic acid methyl ester (1) is described. The first step is a highly regioselective Diels-Alder reaction between 2-methylfuran and methyl-3-bromo-propiolate. A remarkably difficult ketal hydrolysis reaction was effected by treatment with HCl, a simple reagent that was shown to be more efficient, in this case, than commonly used more elaborate methods.
Sobre a síntese de furanoeliangolidos pela reação de Diels-Alder i Summary Sobre a síntese de furanoeliangolidos pela reação de Diels-Alder iii SUMMARY Furanoheliangolides are biologically active natural products containing a 11-oxabicyclo[6.2.1]undecane skeleton. In this work we have investigated two different approaches to synthesize a model of the core structure of goyazensolide (1). Both approaches involve a Diels-Alder reaction and a bond breaking reaction to produce the polycyclic structure.
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