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 ' -biphenoI and 5,5 '-[n-C4F9(CH2)(3)O](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. (C) 2001 Elsevier Science B.V. All rights reserved.