LIGHT-MEDIATED ACTIVATION OF ORGANIC MOLECULES. TOWARD GREENER CHEMICAL TRANSFORMATIONS

OKSDATH-MANSILLA, GABRIELA; BARDAGÍ, JAVIER I.; BUDÉN, MARÍA E.

Anales Asociación Química Argentina

AQA

Año: 2020 vol. 107 p. 134 - 163

2545-8655

The development of new methodologies to replace the classical approach is crucial for sustainable chemical production, since many classical methodologies usually need auxiliary substance, stoichiometric toxic reagent, high temperature (poor energy efficiency), etc. Photoinduced reactions present an excellent opportunity for the development of methodologies environmentally friendly: light is a clean reactive without residual waste. In this context, synthetic organic photochemistry (with and without a photocatalyst) is a powerful tool for creating molecules with high structural complexity, in a simple way, and under mild conditions. Phototransformation could be considered as an alternative synthetic organic tool but, the use of photochemistry with an industrial interest has been limited in regards to the scaling-up of sustainable and safer processes. Recently, the use of continuous-flow technology has been employed successfully to improve several photochemical synthetic applications, providing better control over the conditions of the reaction, selectivity, and reproducibility.Here, we describe the activation of organic molecules in different transformations, driven by light. Particularly, examples will be presented where the light will be used both for the preparation and the functionalization of heterocycles by means of Electron Transfer (ET) reactions. These transformations involve catalytic and non-catalytic oxidative or reductive processes, which generate radical ions and neutral radicals intermediates. Specifically, the reactivity of species derived from carbon, nitrogen, sulfur, and selenium, and their participation in the generation of new C-C and C-heteroatom bonds are discussed. Examples are shown including photocatalytic and base promoted C-H substitutions, cycloaddition reactions, between others presenting also recent advances in the synthesis of compounds with biological and pharmaceutical interest.