Integration of Chiral Phosphine Ligand and Ionic Liquids: Sustainable and Functionally Enhanced BINAP-Based mostly Chiral Ru(II) Catalysts for Enantioselective Hydrogenation of β-Keto Esters†

Herein, a novel class of room temperature chiral phosphine-functionalized polyether imidazolium ionic liquids (RTCP-PolyIMILs) was synthesized for the primary time by ion change response between 5,5′-disulfonato-(S)-BINAP ligand and polyether imidazolium ILs. The interactions with the polyether imidazolium reworked the stable sulfonated BINAP with a excessive melting level right into a room temperature IL, which may act as phosphine ligand and service. Utilizing the engaging twin performance of RTCP-PolyIMILs, an environment friendly and sustainable homogeneous catalysis and biphasic separation system (HCBS) was constructed for Ru(II)-catalyzed enantioselective hydrogenation of β-keto esters to optically lively β-hydroxy esters. Solely a catalytic quantity of RTCP-PolyIMIL was wanted within the absence of any exterior service ILs, permitting the straightforward restoration and recycling of chiral Ru catalyst. The Ru(II)-RTCP-PolyIMIL catalyst confirmed a better exercise and higher adaptability to a variety of solvents than the standard Ru(II)-BINAP catalyst. Particularly, a TOF worth as much as 3900 h-1, enantioselectivity as much as 99%, long-term stability as much as a complete TON worth of practically 17000, extraordinarily low Ru loss price of solely 0.08-0.09%, and good universality for structurally numerous β-keto esters with completely different digital and steric properties had been demonstrated. These dramatic enhancing results could be attributed to the construction of RTCP-PolyIMILs built-in with phosphine ligand and polyether ILs, the place polyether-induced clustering blocking-up and polarity enhancement results performed important roles.