Exploration of the Asymmetric Induction in Ugi Variations Aiming the Stereoselective Synthesis and Functionalizationof N-Heterocycles

Abstract

Since its inception, multicomponent reactions (MCRs) have positioned themselves as an important and powerful tool for the synthesis of compounds with potential biological activity. The great diversity and complexity, generated in a single reactional step, arouse great interest of the pharmaceutical industries. Among the multicomponent reactions, those that exploit the reactivity of isonitriles (isocyanides) are in a prominent position.In this context, the Ugi 4-Component Reaction and its variations appear as unique strategies, which enable the introduction of an amide function in molecular architecture. However, in spite of the advantages offered by these reactions, the lack of control of the stereochemical course during the addition of isonitrile to the pro-chiral carbonyl derivative (kinetic control) - this characteristic hampers the implementation of stereoselective syntheses and is the major limitation of this methodology.Therefore, this project aims to develop new stereoselective methodologies for variations of Ugi reactions, which will have different approaches. Initially the induction of asymmetry by control of the enantioenriched substrate will be evaluated. In this sense, heterocyclic compounds, with a high degree of diversity and structural complexity, will be synthesized through the combination of an organocatalytic step and variations of the Ugi-3-components-4-centers reaction. In a second moment, the induction of asymmetry will be studied by the use of chiral organocatalysts in variations of the Ugi reaction. Through this catalytic approach, several chiral N-heterocycles, with a high degree of substitution, will be synthesized. Finally, in order to better understand the mechanisms of the reactions developed, kinetic and computational studies will be carried out. Further, it is intended, after the synthesis of a wide variety of compounds, to test the biological activity of these compounds.