Single-Molecular Mn(I)-Complex-Catalyzed Tandem Double Dehydrogenation Cross-Coupling of (Amino)Alcohols under Solventless Conditions with the Liberation of H2 and H2O

Sustainable chemical production requires fundamentally new types of catalysts and catalytic technologies. The development of coherent and robust catalytic systems based on earth-abundant transition metals is essential but extremely challenging. Herein, we report the first report on a single Mn(I)-PNP catalyzed tandem C-C and C-N bond formation via double dehydrogenative coupling of amino alcohols with primary alcohols. The current method covers a wide range of substrates, including aryl, aliphatic, acyclic, and cyclic primary alcohols, as well as amino alcohols, to provide diverse N-heterocyclic compounds (pyridine and quinoline derivatives) in good to excellent yields (50 examples). The reaction proceeds under benign, solventless conditions with the liberation of molecular hydrogen and water as the only byproducts. Various control and labeling experiments and kinetic, nuclear magnetic resonance, and mechanistic studies suggest that the reaction operates via the acceptorless double dehydrogenative coupling pathway, selectively assimilating to provide desired N-heterocycles. Several selective bond activation/formation reactions occur sequentially via amine-amide metal-ligand cooperation.

Automated summary

The development of sustainable chemical production requires new catalysts and technologies. Researchers have found that a single Mn(I)-PNP catalysis enables the tandem C-C and C-N bond formation through double dehydrogenative coupling of amino alcohols with primary alcohols, resulting in a wide range of N-heterocyclic compounds. This reaction proceeds under solventless conditions, yielding excellent results with hydrogen and water as the only byproducts.