Metal-free reduction of secondary carboxylic acid amides with hydrogen

• Applicant: Professor Dr. Jan Paradies
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 446999138

The reduction of carboxylic acid amides is a key technology for the synthesis of tertiary and secondary amines. The efficient access to these highly important compound classes is of utmost importance for applications in materials science or in drug synthesis. Usually the reduction of amides is achieved by the reaction with complex hydrides, or, less established, in the presence of transition metal complexes and hydrogen under drastic conditions. However, the metal-free reduction of secondary carboxylic amides by hydrogen is yet without precedence. The project targets this challenge by the development of two intertwined catalytic cycles. Secondary amides will be converted into the imidoyl derivatives by triphosgene or triflic anhydride in the presence of a triaryl phosphane oxide. The reactive imidoyl derivatives undergo frustrated Lewis pair (FLP) catalyzed hydrogenation to yield the secondary amines. This process will not only give access to a broad series of secondary monoamines but will also enable the efficient synthesis of di-, tri and polyamines from readily accessible amide precursors.

• DFG Programme: Research Grants