Catalyse d'hydrogenation en phase homogene des aldehydes α-β insatures. Application a la synthese asymetrique du citronellal

Abstract

Complexes generated in situ from RhHCO(Pø 3) 3 + diphosphine or from Rh 6(CO) 16 or Rh 4(CO) 12 + diphosphine are found to be very efficient homogeneous catalysts for the hydrogenation of α-β ethylenic aldehydes into the corresponding saturated aldehydes. In the presence of the chiral diphosphine (+)- trans-1,2-bis(methylenephosphino)cyclobutane 4, neral is hydrogenated into (+)-citronellal (optical yield: 70 – 79%) and geranial into (—)citronellal (optical yield: 56 – 60%). Other chiral phosphines were also tested.