Recent Advancements in Metal-Free Carbon-Based Catalysts: A Challenge in Sustainable Fine Chemical Synthesis.

The use of metal-free porous carbon catalysts can be considered one of the best alternatives for implementing a more sustainable fine chemical synthesis, as a challenge necessary to protect both our planet and society. It is recognized that the selection of the appropriate functional carbon catalyst, operating under the optimal reaction conditions, undoubtedly improves both the conversion and selectivity of a great variety of distinctive organic transformations, often through cascade reactions or even multicomponent synthesis. Increasing our knowledge of synthetic methodologies for metal-free carbon-based materials (including many of them on a large scale or even at an industrial scale), available characterization techniques, and computational methods represents an excellent opportunity to make these types of materials promising catalysts for a more sustainable future. In this context, this review is addressed to revisit the benefits and limitations of using each type of metal-free porous carbon catalyst in fine chemical synthesis, particularly in multi-bond forming processes for the synthesis of relevant heterocyclic systems.