title: Catalytic hydrogenation with frustrated Lewis pairs: selectivity achieved by size-exclusion design of Lewis acids.
abstract: Catalytic hydrogenation that utilizes frustrated Lewis pair (FLP) catalysts is a subject of growing interest because such catalysts offer a unique opportunity for the development of transition-metal-free hydrogenations. The aim of our recent efforts is to further increase the functional-group tolerance and chemoselectivity of FLP catalysts by means of size-exclusion catalyst design. Given that hydrogen molecule is the smallest molecule, our modified Lewis acids feature a highly shielded boron center that still allows the cleavage of the hydrogen but avoids undesirable FLP reactivity by simple physical constraint. As a result, greater latitude in substrate scope can be achieved, as exemplified by the chemoselective reduction of α,β-unsaturated imines, ketones, and quinolines. In addition to synthetic aspects, detailed NMR spectroscopic, DFT, and (2)H isotopic labeling studies were performed to gain further mechanistic insight into FLP hydrogenation.
authors.affiliation: Institute of Biomolecular Chemistry, Chemical Research Center of Hungarian Academy of Sciences, P.O. Box 17, Budapest 1525, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Eros
authors.forename: Krisztina
authors.initials: K
authors.lastname: Nagy
authors.forename: Hasan
authors.initials: H
authors.lastname: Mehdi
authors.forename: Imre
authors.initials: I
authors.lastname: Pápai
authors.forename: Péter
authors.initials: P
authors.lastname: Nagy
authors.forename: Péter
authors.initials: P
authors.lastname: Király
authors.forename: Gábor
authors.initials: G
authors.lastname: Tárkányi
authors.forename: Tibor
authors.initials: T
authors.lastname: Soós
mesh_terms: D001880:Boranes / Q000737:chemistry; D002384:Catalysis; D006865:Hydrogenation; D058116:Lewis Acids / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011804:Quinolines / Q000737:chemistry
chemical_list: D001880:Boranes; D058116:Lewis Acids; D011804:Quinolines; C037219:quinoline