Iridium-Catalyzed Asymmetric Borylation of Unactivated Methylene C(sp³)–H Bonds

Abstract

Herein, we show the highly enantioselective borylation of unactivated methylene C(sp³)-H bonds in 2-alkylpyridines and 2-alkyl-1,3-azole derivatives using an iridium-BINOL-based chiral monophosphite catalyst system. Quantum chemical calculations using the artificial force induced reaction (AFIR) method suggested that a monophosphite-Ir-tris(boryl) complex generates a narrow chiral reaction pocket where the differentiation of the enantiotopic methylene C-H bonds is accomplished through an assembly of multiple noncovalent interactions.