Síntese de Seleno-Isoxazóis e Seleno-Indóis via Reações de Ciclização Intramolecular mediadas por Cloreto Férrico

Detalhes bibliográficos
Ano de defesa: 2013
Autor(a) principal: Sperança, Adriane
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Santa Maria
BR
Química
UFSM
Programa de Pós-Graduação em Química
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.ufsm.br/handle/1/4241
Resumo: This work reports the synthesis of a series of 4-organoselenyl-isoxazoles (19 examples), prepared via FeCl3/diorganyl diselenides-promoted intramolecular cyclization of alkynone O-metyloximas. In general, the selenyl-isoxazoles were obtained, in 50 to 70% yield. In addition, an alternative method was developed to promote the intramolecular cyclization reaction of o-alkynyl-N,N-dimethyl-anilines, where FeCl3 and substituted diorganyl diselenides were employed as promoter agents to this process. Through this cyclization protocol a series of N-methyl-3-organoselenyl-indoles could be synthesized (20 examples), in yields varying from 36 to 81%, by using room temperature and ambient atmosphere. In order to evaluate the versatility of the obtained compounds as precursors to the synthesis of functionalized isoxazoles and indoles, the 3,5-diphenyl-4-(phenylselenyl)-isoxazole, N-methyl-2-phenyl-3-(phenylselenyl)-1H-indole and N,5-dimethyl-2-phenyl-3-(phenylselenyl)-1H-indole were submitted to PhSe-Lithium exchange reactions, and the corresponding organolithium intermediates, which were generated by treatment with nBuLi, could be trapped with different electrophiles, affording the functionalized isoxazoles (5 examples) and indoles (4 examples) in good yields (45-80%).