One central challenge for XXI century chemists is the development of sustainable processes that do not represent a risk either to humanity or to the environment. In this regard, the search for more efficient and clean alternatives to achieve the chemical activation of molecules involved in chemical transformations has played a prominent role in recent years. The use of microwave or UV-Vis light irradiation, and mechanochemical activation is already widespread in many laboratories. Nevertheless, an additional condition to achieve “green” processes comes from the point of view of so-called atom economy. The removal of solvents from chemical reactions generally leads to cleaner, more efficient and more economical processes. This review presents several illustrative applications of the use of sustainable protocols in the synthesis of organic compounds under solvent-free reaction conditions.

The application of six novel α,β-dipeptides as chiral organocatalysts in the asymmetric Michael addition reaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMAP) and thiourea as a hydrogen bond donor proved to be highly efficient organocatalytic systems in the enantioselective reaction between isobutyraldehyde and various nitroolefins.

The use of the solvent engineering has been applied for controlling the resolution of lipase-catalyzed synthesis of β-aminoacids via Michael addition reactions. The strategy consisted of the thermodynamic control of products at equilibrium using the lipase CalB as a catalyst. The enzymatic chemo- and enantioselective synthesis of (R)-(−)-N-benzyl-3-(benzylamino)butanamide is reported, showing the influence of the solvent on the chemoselectivity of the aza-Michael addition and the subsequent kinetic resolution of the Michael adduct; both processes are catalyzed by CalB and both are influenced by the nature of the solvent medium. This approach allowed us to propose a novel one-pot strategy for the enzymatic synthesis of enantiomerically enriched β-aminoesters and β-aminoacids.

Uno de los principales retos para los químicos de hoy consiste en el desarrollo de procesos amigables con el medio ambiente. Histórica-mente, no había un interés por analizar el impacto de los reactivos, ca-talizadores y disolventes en cuanto a su toxicidad y degradación. Lo anterior ha puesto en peligro a numerosas especies y también la salud de diversas poblaciones que han sido expuestas a estos compuestos. Ahora, los gobiernos y las empresas han impulsado un nuevo enfoque en la manera de hacer química priorizando la preservación de nuestro entorno. Ese nuevo enfoque es la llamada Química Verde. Este ar-tículo describe a modo general, los avances en el grupo del Dr. Eusebio Juaristi (Profesor Emérito del Departamento de Química del Cinves-tav) en el área de la Química Verde y en particular en el uso de la Me-canoquímica como herramienta sustentable en la síntesis de compues-tos orgánicos.