Hydrogenations at Room Temperature and Atmospheric Pressure with Mesoionic Carbene‐Stabilized Borenium Catalysts

Abstract

1,2,3-Triazolylidene-based mesoionic carbene boranes have been synthesized in a convenient one-pot protocol from the corresponding 1,2,3-triazolium salts, base, and borane. Borenium ions are obtained by hydride abstraction and serve as catalysts in mild hydrogenation reactions of imines and unsaturated N-heterocycles at ambient pressure and temperature.

Solid frustrated-Lewis-pair catalysts constructed by regulations on surface defects of porous nanorods of CeO2

“…Hydrogen activation by either transition metal complexes or metal-based heterogeneous catalysts have been well developed and successfully applied for various reactions4. Recently, frustrated Lewis pairs (FLPs), Lewis acids and bases that are sterically prevented from interaction to form Lewis acid–base adjuncts, can efficiently and cooperatively activate many small molecules (for example, H 2 , CO 2 , and NO) and even strong C–H bond for important catalytic reactions including hydrogenation, hydroamination and carbon dioxide reduction5678910111213141516171819202122232425.…”

Non-conventional Lewis Acids and Bases in Frustrated Lewis Pair Chemistry

“…Shortly after our reports, Crudden and coworkers reported the synthesis of mesoionic carbene-stabilized borenium cations [33]. It was reasoned that a triazole-derived mesoionic carbene coordinated to a borane yields a more hydridic B-H fragment than the related NHC derivatives [34] and thus a more effective [36].…”

Main Group Lewis Acids in Frustrated Lewis Pair Chemistry: Beyond Electrophilic Boranes

“…Crudden and co-workers 56 recently described a related series of triazolium-derived borenium cations and their use in the reduction of imines and N-heterocycles at atmospheric pressure. Their findings similarly support the notion that low steric demand and a careful balance in the donor ability of the carbene is required for optimal catalytic activity.…”