Síntese estereosseletiva de α-fenilseleno-β-amino ésteres pela reação do tipo-Mannich e efeito promotor de tiofenol na reação de Pictet-Spengler.
Ano de defesa: | 2006 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
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
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Departamento: |
Não Informado pela instituição
|
País: |
Não Informado pela instituição
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Palavras-chave em Português: | |
Link de acesso: | http://repositorio.ufsm.br/handle/1/4186 |
Resumo: | In the present work, it was developed a new methodology for the stereoselective synthesis of α-phenylseleno-β-amino esters by the Mannich-type reaction. These reactions involve chlorotitanium α-phenylseleno esters enolates and aromatic aldimines, affording preferentially the syn-α-phenylseleno-β-amino esters 3a-l in reasonable to good diastereoselectivity, and in 67% to 86% yield. The reactions were carried out with aromatic aldimines with differents substitution paterns in the aromatic ring. Testing the reactivity and the synthetic potential of the α-phenylseleno-β-amino esters, it was observed that the compound 3a reacts with LiHMDS in mild reaction conditions to aford the corresponding anti-α-phenylseleno-β-lactam 4 in 57% yield. Additionally, it was developed an efficient methodology for the synthesis of 1,2,3,4-tetrahydroisoquinolines 7 substituted in the carbon 1, by the activated Pictet-Spengler reaction in the presence of thiophenol, which produces a considerable promoting effect. This reaction was performed with N-tosyl-β-phenethylamines 5 and phenylthioacetals, which were produced 'in situ' by the reaction of thiophenol with an aldehyde under BF3.Et2O catalysis, affording the 1,2,3,4-tetrahydroisoquinolines 7 in 66 to 94% yield. |