Reações do tipo Michael na síntese de compostos multifuncionalizados via organocatálise

• Ano de defesa: 2018
• Autor(a) principal: Fernandes, Raony Bronzatto Garcia [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Organocatalysis; Stereoselective catalysis; Michael addition; Organic synthesis; α,β-unsaturated cyanoesters; Organocatálise; Catálise estereosseletiva; Adição de Michael; Síntese orgânica; Cianoésteres α, β-insaturado
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=6371593; https://repositorio.unifesp.br/handle/11600/52786

This work consists in the continuity of a project initiated by other researchers in our research group dealing with the theme of conjugated addition, or Michael reaction, to obtain enantioselectively functionalized nitro-cyanoesters, applying bifunctional organocatalysts for the addition catalysis. In the structures of the organocatalysts are the functional groups thiourea and tertiary amine, featuring its type of operation, known as bifunctional catalysis. 26 organocatalysts were tested, varying conditions as solvent and reaction time, obtaining the enantiomeric excess (ee) of 59%, at 0 °C in chloroform for the Michael reaction between the model cyanoester and nitromethane. To verify the scope of the Michael reaction studied, 14 structurally different α,β-unsaturated cyanoesters were prepared from corresponding aldehydes, obtaining them in yields of 24 to 81%. The Michael reaction was carried out in an achiral medium in order to obtain the adducts in racemic mixture for later analyzes in HPLC (High Performance Liquid Chromatography) to identify the behavior of the peaks of the stereoisomers obtained, yields were 7% to quantitative. Two organocatalysts were tested on Michael's double addition followed by intramolecular ring closure (MIMIRC), obtaining conversion rates of 79-85% for the novel compound diethyl 5'-amino-4'-cyano-2'-nitro-1',2',3',4'- tetrahydro-[1,1':3',1''-terphenyl]-4',6'-dicarboxylate.