Green Catalysts and/or Green Solvents for Sustainable Multi-Component Reactions

Here, we describe some well-known multicomponent reactions and the progress made over the past decade to make these processes even more environmentally friendly. We focus on the Mannich, Hantzsch, Biginelli, Ugi, Passerini, Petasis, and Groebke–Blackburn–Bienaymé reactions. After describing the origin of the reactions and their mechanisms, we summarize some advances in terms of the eco-compatibility of these different MCRs. These are followed by examples of some reactions, considered as variants, which are less well documented but which are promising in terms of structures generated or synthetic routes.