Multicomponent Reactions appear to be ideal for any form of synthesis, because of their numerous advantages in terms of sustainability and selectivity in building up complex molecular architectures, with high molecular diversity. This Special Issue collects seven contributions which expand our knowledge about Multicomponent Reactions, providing a good overview about innovative reactivities and applications.

In the present article the 1,4-dioxane derivative 1, a potent noncompetitive NMDA receptor antagonist, showed cytotoxic activity in the MCF7 breast cancer cell line significantly higher than those of the functionally related compounds (S)-(+)-ketamine and MK-801. Encouraged by this result and considering that copper complexes have been highlighted to be promising anticancer agents, the NMDA receptor ligand 1 was linked to the bifunctionalizable species 2 and 3, affording the conjugated derivatives 4 and 5 that were used for the preparation of the stable Cu(II) complexes 6 and 7. All the compounds were evaluated against a panel of human cancer cell lines derived from solid tumors. Complex 7 showed the best antitumor activity in all the studied cell lines. This result suggests that 7 might act through synergistic mechanisms of action due to the presence of the NMDA ligand 1 and copper(II) in the same chemical entity. Furthermore, the cellular mechanisms affected by complex 7 were assessed through cytofluorimetric and western blot analyses. Data suggested the induction of cell death through paraptosis mediated by endoplasmic reticulum (ER) stress.

An easy and efficient synthetic methodology for the one-pot stereocontrolled synthesis of tetrahydroquinolines through Lewis acid activated Povarov reaction is described. The protocol takes advantage of the very cheap, easy to handle, and environmentally friendly cerium trichloride as catalyst and allows to obtain either the anti- or the syn-isomer of the final tetrahydroquinoline with good selectivity, by performing the reaction in solvent or solventless conditions. The scope of the reaction is expanded to the one-pot synthesis of N-alkyltetrahydroquinolines through a very efficient iminium-Povarov approach. A deeper insight on the reaction system was provided by the study on the side reactions occurring in the reaction conditions and on the nature of the stereoselectivity.