multicatalysis

Multicatalysis refers to chemical catalysis in which two or more distinct catalytic cycles operate within a single reaction system to convert substrates into products through multiple transformations. The approach enables tandem or cascade reactions, where the product of one catalytic step becomes the substrate for the next, often without isolating intermediates.

Formats include one-pot tandem catalysis, cooperative catalysis where catalysts interact to enhance reactivity, orthogonal catalysis with catalysts that function under complementary conditions without mutual deactivation, and compartmentalized multicatalysis in which different catalysts are spatially separated yet function in the same overall process. These designs can use homogeneous or heterogeneous catalysts, metal complexes, organocatalysts, or enzymes, and may combine biocatalysis with chemocatalysis.

Benefits of multicatalysis include higher atom economy, reduced workup, shorter synthesis, access to otherwise difficult transformations, and potential for improved selectivity and sustainability. Challenges involve compatibility of catalysts and substrates, mutual deactivation, leaching, catalyst poisoning, solvent and temperature constraints, product inhibition, and separation or recovery of catalysts.

Applications span the synthesis of pharmaceuticals and fine chemicals, materials science, and polymerization/copolymerization cascades. Common themes include tandem oxidation/condensation, hydrogenation followed by functionalization, and cross-coupling-initiated rearrangements, all designed to streamline complex sequences in a single process.

Future directions focus on design principles for catalyst compatibility, the use of orthogonal catalysts, immobilization and flow chemistry to enable scalable multicatalysis, and integration with automation and AI to optimize reaction conditions and catalyst combinations.