Heterolytic dihydrogen activation by "antagonistic" Lewis pairs

• Applicant: Professor Dr. Gerhard Erker
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2009 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 88491225

Hydroboration of a series of enamines with Piers’ borane gave new intramolecular vicinal N/B frustrated Lewis pairs (FLPs). These examples feature weak intramolecular nitrogenboron interactions. The activation barrier for ring opening to the active FLPs was determined for chiral examples by dynamic 19F NMR spectroscopy. Similar P/B FLPs were prepared and the activation barrier of the cleavage of their weak P−B bonds determined as well. Many of these new systems cleave dihydrogen heterolytically under mild conditions. Some serve as metal-free catalysts for the hydrogenation of electron-rich unsaturated substrates (enamines, dienamines, imines, etc.). We have also developed a protocol for FLP catalyzed hydrogenation of electron-poor olefins and alkynes (bulky ynones and enones). This has considerably extended the application potential of these new metal-free main-group element dihydrogen activators.

• DFG Programme: Research Units
• Subproject of: FOR 1175: Unconventional Approaches to the Activation of Dihydrogen