Catálise orgânica estereosseletiva para reações de adição do tipo Michael de nitrometano em cianoésteres α,β-insaturados

• Ano de defesa: 2017
• Autor(a) principal: Teixeira, Andrews Loys Silveira [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• dARK ID: ark:/48912/001300001w8q1
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Organic catalysis; Michael addition; Stereoselective catalysis; Organic synthesis; α, β-unsaturated cyanoesters; Organocatálise; Catálise estereosseletiva; Adição de Michael; Síntese orgânica; Cianoésteres α, β-insaturados
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5883130; http://repositorio.unifesp.br/handle/11600/49947

This work aimed the performance of the enantioselective Michael addition of nitromethane in α, β-unsaturated cyanoesters. Organic catalysts based in the alkaloids from de group Cinchona were used. In their structure there are two functional important groups, tertiary amine and thiourea, which both characterize the type of catalysis, known as bifunctional catalysis. To verify the Michael reaction’s reactivity, 14 different α, β-unsaturated cyanoesters were prepared from corresponding aldehydes, obtaining yields of 24 to 81 %. The Michael reaction was performed using an achiral catalyst to obtain the products in racemic mixture. Those racemic mixtures were used for High Performance Liquid Chromatography (HPLC) analysis to separate the stereoisomers obtained. Two organic catalysts were tested, varying conditions as temperature, solvent and reactional time. The best enatiomeric excess (ee) was 50%, at 0° C in chloroform. With the results, it was possible to propose a mechanism of the organic catalysts’ action.