화학공학소재연구정보센터
Science, Vol.369, No.6506, 970-+, 2020
Asymmetric remote C-H borylation of aliphatic amides and esters with a modular iridium catalyst
Site selectivity and stereocontrol remain major challenges in C-H bond functionalization chemistry, especially in linear aliphatic saturated hydrocarbon scaffolds. We report the highly enantioselective and site-selective catalytic borylation of remote C(sp(3))-H bonds ( )gamma to the carbonyl group in aliphatic secondary and tertiary amides and esters. A chiral C-H activation catalyst was modularly assembled from an iridium center, a chiral monophosphite ligand, an achiral urea-pyridine receptor ligand, and pinacolatoboryl groups. Quantum chemical calculations support an enzyme-like structural cavity formed by the catalyst components, which bind the substrate through multiple noncovalent interactions. Versatile synthetic utility of the enantioenriched gamma-borylcarboxylic acid derivatives was demonstrated.