Solvent-Switchable Remote C-H Activation via 1,4-Palladium Migration Enables Site-Selective C-P Bond Formation: A Tool for the Synthesis of -Chiral Phosphinyl Imidazoles.

Solvent-switchable and site-selective phosphorylation of imidazoles at the C2 or C5 position of the imidazole ring was achieved via 1,4-palladium migration. -Chiral -butyl(aryl)phosphine oxides were cross-coupled to 1-(2-bromophenyl)-1-imidazoles with high enantiospecificity, thereby leading to a novel class of chiral imidazole-based phosphine oxides. As proof of concept, reduction of an analogue yielded the corresponding -chiral 2-phosphinyl imidazole ligand, which was shown to induce high enantioselectivity in the formation of axially chiral molecules synthesized via Pd-catalyzed Suzuki-Miyaura cross-coupling.

P-Chiral, N-phosphoryl sulfonamide Brønsted acids with an intramolecular hydrogen bond interaction that modulates organocatalysis.

Brønsted acids exemplified by OttoPhosa I (5c) were designed and evaluated in the asymmetric transfer hydrogenation of quinolines. Their catalytic properties are modulated by an intramolecular hydrogen bond that rigidifies their catalytic cavity, accelerates the reaction rate and improves enantioselectivity.