Funcionalización de enlaces c-h mediante catálisis asistida por microondas

Resumen

The synthesis of organic molecules with applications in medicine, agriculture, energy, and materials development, among others, has garnered significant attention in recent years. Direct functionalization techniques of C-H bonds have received particular interest due to the reduction in the number of reaction steps required to achieve the desired structural complexity. Due to the abundance of C-H bonds present in organic molecules, reactions with specific characteristics of regioselectivity, chemoselectivity, and stereoselectivity are often required, and can be facilitated using catalysts. However, some C-H bond functionalizations may involve the use of toxic substances, long reaction times (resulting in high energy consumption), or the generation of significant waste or by-products. The methodologies developed in this PhD thesis adhere to the principles of Green Chemistry. Notable features include the utilization of microwave radiation and ultrasound, solvent-free and one-pot procedures, non-metallic catalysts, and low impact metal nanocatalysts. All this will allow to carry out the formation of various types of C-X bonds (X = O, P, S and N) in a more sustainable way. The research conducted in this Ph.D. thesis has been focused on studying, developing, and optimizing three distinct types of oxidations, all of which have been facilitated by microwave assistance. Article 1 reports on the formation of C-O bonds via the TBAI/TBHP tandem, involving the coupling of liquid ketones or cyclic ethers with carboxylic acids. Article 2 explores the use of a nanocatalyst based on a mixed oxide of copper and iron to expand the previous coupling to aldehydes and to the Kharasch Sosnovsky reaction. Article 3 presents the oxyphosphorylation of alkynes through an organometallic copper (I) catalyst in homogeneous phase, leading to the formation of C-P bonds. Finally, Article 4 delves into the oxidation and chlorination of alcohols using the TCCA/TEMPO system, culminating in the creation of molecules with potential biological activity, including notable compounds like thiazoles.