Development of nanoporous metal skeleton catalysts for organic synthesis

Nanoporous metal skeleton catalysts are becoming increasingly important in the field of green and sustainable chemistry, due to their high catalytic activities and selectivities together with their robust characteristics. Nanoporous metals (MNPores) are fabricated through chemical or electrochemical corrosive dealloying of monolithic alloys, which produces various MNPores with open network nanoporous structures. The large surface-to-volume ratio compared to bulk metals, together with high density of steps and kinks on ligaments make them promising heterogeneous catalysts having highly active and selective characteristics for molecular transformations. We have developed a variety of heterogeneous catalytic reactions using MNPores primarily under liquid-phase (or liquid-gas phase) conditions. Oxidation of C-OH with O2 and Si-H with H2O gives C=O and Si-OH bond, respectively. Selective reduction of C=C, C=C, C=N, C=N, and C=O bonds proceeds smoothly with MNPores, whose selectivities are not easily attainable through previously known catalysts. Cross-dehydrogenative coupling, diboration, C-C bond cross-coupling reaction, azide-alkyne click reaction, and hydrosilylation can be catalyzed selectively and efficiently with MNPores. © 2020 Society of Synthetic Organic Chemistry. All rights reserved.