Reações de bromoaminociclização enantiosseletivas promovidas por organocatalisadores
Data
2021-04-07
Autores
Matsushima, Jullyane Emi 
Orientadores
Rodrigues, Alessandro
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Este trabalho teve como foco promover e estudar reações de bromoaminociclização enantiosseletivas. O álcool alílico e, principalmente, seus análogos estruturais são compostos orgânicos de grande interesse à comunidade acadêmica, uma vez que permitem uma gama de transformações químicas. Neste sentido, esta dissertação apresenta o desenvolvimento de uma nova versão enantiosseletiva de reações de bromoaminação intramolecular de derivados de álcoois alílicos (N-tosilcarbamatos) promovidas por organocatalisadores derivados de alcaloides do gênero Cinchona. A utilização de organocatalisadores se apresenta como uma alternativa a utilização de metais, abrangendo mais aspectos da química verde. O produto de bromoaminação do N-tosil-alilcarbamato foi obtido em até 60% de excesso enantiomérico e 41% de rendimento. A reação se apresenta diastereoespecífica, com a formação de apenas produtos de adição trans à olefina e régioespecífica pela formação exclusiva de anéis de 6 membros. Paralelamente aos estudos de catálise, com o auxílio da espectrometria de massas, foi possível propor um ciclo-catalítico para a reação de bromoaminação desenvolvida, pela identificação de intermediários reativos. Com este trabalho, espera-se cooperar com o aumento e a diversificação da produtividade científica e tecnológica da pesquisa brasileira além de se ampliar os conhecimentos de química orgânica que possam ser úteis para a comunidade científica.
This work focused on promoting and studying enantioselective bromoaminocyclization reactions. Allyl alcohol and, mainly, its structural analogues are organic compounds of great interest to the academic community, since they allow a range of chemical transformations. In this sense, this dissertation presents the development of a new enantioselective version of intramolecular bromoamination reactions of derivatives of allyl alcohols (N-tosylcarbamates) promoted by organocatalysts derived from alkaloids of the genus Cinchona. The use of organocatalysts is an alternative to the use of metals, covering more aspects of green chemistry. The bromoamination product of N-tosyl-allylcarbamate was obtained in up to 60% enantiomeric excess and 41% yield. The reaction is diastereospecific, with the formation of only products with trans addition to olefin and regiospecific by the exclusive formation of 6-membered rings. In parallel with the catalysis studies, with the aid of mass spectrometry, it was possible to propose a catalytic cycle for the developed bromoamination reaction, by identifying reactive intermediates. With this work, we hope to cooperate with the increase and diversification of the scientific and technological productivity of Brazilian research, in addition to expanding the knowledge of organic chemistry that may be useful for the scientific community.
This work focused on promoting and studying enantioselective bromoaminocyclization reactions. Allyl alcohol and, mainly, its structural analogues are organic compounds of great interest to the academic community, since they allow a range of chemical transformations. In this sense, this dissertation presents the development of a new enantioselective version of intramolecular bromoamination reactions of derivatives of allyl alcohols (N-tosylcarbamates) promoted by organocatalysts derived from alkaloids of the genus Cinchona. The use of organocatalysts is an alternative to the use of metals, covering more aspects of green chemistry. The bromoamination product of N-tosyl-allylcarbamate was obtained in up to 60% enantiomeric excess and 41% yield. The reaction is diastereospecific, with the formation of only products with trans addition to olefin and regiospecific by the exclusive formation of 6-membered rings. In parallel with the catalysis studies, with the aid of mass spectrometry, it was possible to propose a catalytic cycle for the developed bromoamination reaction, by identifying reactive intermediates. With this work, we hope to cooperate with the increase and diversification of the scientific and technological productivity of Brazilian research, in addition to expanding the knowledge of organic chemistry that may be useful for the scientific community.