N-S Bond formation mediated by Hypervalent Iodine Reagents

• Autor(a) principal: Caldeira, Catarina Isabel Pedro Seixas
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/147381
• topic: Sulfonylation; Amination; Hypervalent Iodine Reagents; Sulfonamides; N-Aminosulfonamides; Umpolung; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

The sulfonamide and N-aminosulfonamide groups are key scaffolds for both synthetic and medicinal chemistry, belonging to the well-known ''sulfa drugs''. Despite their importance and wide usefulness, the methods for the preparation of these classes of compounds present some limitations, such as the handling of sulfur dioxide and the use of additives and transition metals. In this project, several sulfonamides and N-aminosulfonamides were synthesized, using hypervalent iodine reagents. These reagents assume a structure and reactivity similar to transition metals and have emerged as versatile reagents for various chemical transformations in organic synthesis. Our group has been investigating hypervalent iodine reagents as group-transfer reagents, exploiting the polarity inversion, that is, the umpolung reactivity of benziodoxolone-based reagents. On the follow-up of our research, we have considered the potential of hypervalent iodine reagents for S-N bond formation and investigated the sulfonylation of hydrazines and amination of sulfenates. Chlorobenziodoxolone was used to generate in situ a sulfonyl benziodoxolone intermediate, that reacted with hydrazines in MeCN at -40ºC, affording 19 different N-aminosulfonamides in up to 56% yield. In a second part of his project, the recently disclosed benzylaminobenziodoxolone reagent was investigated in the amination reaction of sulfenates. This iodine(III) reagent reacted with different sulfenates in DMF at 50ºC, affording 4 different sulfonamides in yields up to 52%. Considering the biological and medicinal relevance of compounds possessing the S-N bond, herein, two novel approaches were developed to achieve this class of compounds.