Heat-Induced Granular Motion in Quasi-Solid-State Suzuki-Miyaura Reaction

Solid-state cross-coupling is a promising synthetic strategy, enabling green processes and access to otherwise unattainable products. To date, avoiding the harsh mechanical force while achieving the synthesis of highly insoluble materials under mild, additive-free, and solid-state conditions remains a challenge especially if heterogeneous catalysis is considered. Inspired by the fundamental diffusion dynamics observed in nature, we developed a polymeric palladium-catalyzed quasi-solid-state Suzuki-Miyaura reaction that proceeds without mechanical input; that is, a granular motion of the components results from heat-induced convection-driven mass transfer. This approach enabled the synthesis of various polycyclic aromatic hydrocarbons and functional materials in up to 93% yields with Pd loadings as low as 500 mol ppm. Gram-scale synthesis of dinaphthyl anthracene as a functional material was successfully achieved under the quasi-solid-state reaction conditions. Notably, since no mechanical force is applied during the reaction, it is well-suited to be analyzed in real time, which is a challenge in solid-state systems. As a result, in-situ monitoring of the chemical changes of each of the solid reactants allowed the identification and real time monitoring of a boronate intermediate. In addition, direct microscopic visualization revealed changes in morphology and element distributions, proposing a granular motion mechanism for this transformation.