Estudo visando a síntese da (-) - putaminoxina

• Ano de defesa: 2014
• Autor(a) principal: Vassiliades, Sandra Valeria [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Putaminoxin; Decalactone; Ring-closing olefin metathesis; Enzymatic kinetic resolution; Medium size lactone; Putaminoxina; Decalactona; Metátese olefínica de fechamento de anel; Resolução cinética enzimática; Lactona de anel médio
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=1361325; http://repositorio.unifesp.br/handle/11600/47654

The ()-putaminoxin is a natural decalactone isolated from the culture of Phoma putaminuim fungus, which showed phytotoxic activaty against several plants. This dissertation report our studies aiming at the synthesis of ()-putaminoxin, using as a key steps a ring-closing olefin metathesis, to prepare the lactone motiety, and enzymatic kinetic resolution to define the C5stereogenic center of lactone. The enzymatic kinetic resolution was carried out with allyl alcohol ()-I using four enzymes in different reaction times. Regarding the preparation of ()- putaminoxin, firstly we obtained a racemic key fragment (IV). In order to obtain III, alternative methods of oxidation were tested, and for preparation of IV two classic sterification strategies were studied (Yamaguchi and DCC). For this step, we evaluated the use of dimethyl carbonate as alternative solvent. Although many efforts have been concentrated on the preparation of lactones ()-V, which after deprotection would lead to ()-putaminoxin, we obtained a mixture theof diasteroisomers of ()-V, which was difficult to separate and, therefore, not allowing us to unambiguously elucidate the structural of the compounds prepared so far.