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Radical arilations of endocyclic encarbamates by fotoredox: development of the new method, derivatization, and synthetic applications

Grant number: 19/25657-9
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): March 01, 2020
Effective date (End): February 29, 2024
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Organic Chemistry
Principal researcher:Carlos Roque Duarte Correia
Grantee:Edson Leonardo Scarpa de Souza
Home Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
Associated research grant:14/25770-6 - New frontiers in cross-coupling reactions promoted by palladium: combining enantioselective catalysis, C-H activations, new materials and in flux reactions aiming at high efficiency and sustainability in synthetic processes, AP.TEM

Abstract

Aromatic rings are present in numerous bioactive substances, natural or synthetic, and reactions aimed at arylating olefins have long been established as one of the most efficient catalytic processes. In this sense, the metal catalysis has predominated, being palladium the most used metal (Heck reaction). However, this decade experiences an exponent growth of works using photoredox conditions, where ruthenium and iridium complexes are employed. These methods allow the arylation of olefin with regioselectivity inverse to that of the Heck reaction, which allows reaching new products with high aggregate synthetic value as well as advanced intermediates in the synthesis of natural products and biologically active substances. A very useful synthetic tool to achieve these goals is the arenediazonium salts. These compounds are readily accessible synthetically and represent an important building block class in organic synthesis. The inverse regioselectivity of arylations arises from the difference in the reaction mechanisms of these two processes. Additionally, arylations following the photoredox model of some electron-rich olefins, such as enecarbamates, allow the reach of N-acyliminium intermediates, which can potentially be captured with nucleophiles, generating important products by functionalizing alpha positions to nitrogen. Such functionalities present enormous synthetic flexibility by allowing exchanges for other groups (nucleophiles), such as, for example, nitriles, the formation of C-C bonds involving electron-rich aromatic systems, allyl systems, and malonate type systems, among many others. Cyclization reactions involving nucleophile exchange are also within the reach of the method. (AU)

News published in Agência FAPESP Newsletter about the scholarship: