Synthesis of Pyridyl-dihydrobenzooxaphosphole Ligands and Their Application in Asymmetric Hydrogenation of Unfunctionalized Alkenes

Synthesis of the electron-rich 2-substituted-6-(phenyl­sulfonyl)­pyridines is presented. A series of air-stable, tunable, P-chiral pyridyl-dihydrobenzooxaphosphole ligands were designed and synthesized by a diastereoselective SNAr substitution of the corresponding sulfonyl pyridines. The ligands were successfully applied in the Ir-catalyzed asymmetric hydrogenation of unfunctionalized alkenes with good enantioselectivities.