ENANTIOSELECTIVE CATALYSIS BY 1-(1-ISOQUINOLINVL)-2-NAPHTHALENEMETHANOL - AN ATROPISOMERICALLY CHIRAL N-O CHELATING LIGAND

Racemic 1-(1-isoquinolinyl)-2-naphthalenemethanol 6 has been prepared through a ligand coupling reaction of racemic 1-(tert-butylsulfinyl)isoquinoline 2 with the 1-naphthyl Grignard reagent 4. Resolution of the ligand 6 was achieved through chromatographic separation of the Noe-lactol(R) derivatives. The absolute configuration of (R)-(-)-6 was determined by a single crystal X-ray study of the p-bromobenzoate derivative 9. (R)-(-)-6 enantioselectivity catalysed the addition of diethylzinc to benzaldehyde, affording (S)-(-)-1-phenyl-1-propanol in 68% e.e.