Design and synthesis of new fluorinated ligands for the rhodium-catalyzed hydroformylation of alkenes in supercritical CO2 and fluorous solvents

Novel fluorous biphenols, 5,5′-[n-C4F9(CH2)3]2-2,2′-biphenol and 5,5′-[n-C4F9(CH2)3O]2-3,3′-di-tert-butyl-2,2′-biphenol, as well as enantiopure BINOLs, (S)-6,6′-[n-C4F9(CH2)3]2-BINOL, (R)-6,6′-[n-C6F13(CH2)3]2-BINOL, and (S)-6,6′-[n-C8F17(CH2)3]2-BINOL, are synthesized. These compounds serve as key intermediates for the syntheses of a variety of new fluorous ligands for regioselective and enantioselective catalytic reactions. Novel fluorous [Rf(CH2)3]2-BINAPHOS ligands (Rf=n-C4F9, n-C6F13, and n-C8F17) are successfully synthesized. These new fluorous chiral ligands when used with a rhodium catalyst can achieve comparable or even higher regioselectivity and enantioselectivity in the asymmetric hydroformylation of styrene as compared to those by the Rh-BINAPHOS system.