Rapid and Practical Transfer Hydrogenation for Cleavage of N-Cbz Protected Amines Using a Supported Palladium Catalyst Under Microwave Irradiation

Hydrogenation reactions are commonly employed to reduce organic functional groups, but traditional approaches often rely on hazardous compressed gases and pyrophoric catalysts. Motivated by the need for safer and more practical alternatives, we developed a broadly applicable protocol for Cbz group removal that avoids both flammable Pd/C and hydrogen cylinders. Instead, we utilize SiliaCatPd(0)a commercially available, sol-gel supported palladiumwhich has demonstrated effectiveness in debenzylation processes. The unique sol-gel matrix of this catalyst minimizes metal leaching and mitigates the risks associated with pyrophoric palladium sources. Leveraging these advantages, our method offers a safer and more convenient route for hydrogenation in everyday laboratory practice. Specifically, we present a transfer hydrogenation system using this supported palladium catalyst for the selective deprotection of Cbz-protected amines, designed to streamline medicinal chemistry workflows with rapid setup and execution in a microwave reactor.