Estudo metodológico de reações aldólicas organocatalisadas em solventes não convencionais

• Ano de defesa: 2015
• Autor(a) principal: Silva, Rubia Yano da [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; Aldol reactions; Asymmetric synthesis; Green chemistry; Reactions in water; Organocatálise; Reações aldólicas; Síntese assimétrica; Química verde; Reações em água
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=2356544; http://repositorio.unifesp.br/handle/11600/47477

Organocatalysis is a methodology in which a substoichiometric amount of a low-molecular mass organic compound is used to speed up chemical reactions, without necessity of metal presence. Since 2000, the organocatalyzed aldol reaction has attracted a great deal of attention and became an intensively active research topic, because it can be applied in the stereoselective synthesis of asymmetric molecules providing high efficiency and selectivity. Nowadays, efforts have also been dedicated to the design of new organocatalysts that provides high levels of stereoselectivity, are recyclable and also used in an environmentally cleaner reaction media. Thus, this work aims to study asymmetric aldol reactions promoted by new fluorinated organocatalysts derived from proline that were prepared and then applied in the aldol reaction under different reaction conditions. The products of the reaction between ciclohexanone and p-nitrobenzaldehyde were obtained in a range from 10% to 96% and the best result was achieved in a solvent-free condition, with a 89:11 anti:syn ratio and with an enantiomeric excess of >99%. The evaluation of stereoselectivity was performed using different aldehydes and ketones, and the study about recycling organocatalyst demonstrated that it could be easily recycled and reused. The application of fluorinated organocatalysts in organocatalized aldol reaction proved to be very promising in a solvent-free condition. The synthesis of ?-hydroxy ketones, the products that should be obtained from these reactions, will allow the application of this methodology in asymmetric synthesis of bioactive molecules efficiently, elegant and with reduction of chemical waste.