Excellent diastereoselectivity (dr value up to 100 : 0) was achieved in DMAP-catalyzed P–N bond formation in the synthesis of P-chirogenic organophosphines from phenylphosphonic dichloride (PhP(O)Cl2) and (S)-2-pyrrolidinemethanol derivatives. Investigations using NMR spectroscopy and calculations revealed the formation of a bimolecular complex from (PhP(O)Cl2) and revealed DMAP as an ‘active phosphonyl’
New chiral phosphinamide catalysts for highly enantioselective reduction of ketones
作者:Mark P. Gamble、John R. Studley、Martin Wills
DOI:10.1016/0040-4039(96)00404-2
日期:1996.4
A novel class of recoverable and highly stable phosphinamide catalysts for the asymmetric reduction of ketones by borane is described. Enantiomeric excesses of up to 92% have been obtained using 10 mol% of the optimum catalyst.
New enantioselectivecatalysts for the asymmetric reduction of ketones by borane are described. Easilyprepared by oxidation of chiral oxazaphospholidines, these compounds increase sensitively the reduction rate of numerous ketones and induce ee's up to 94% in the case of the 2-chloroacetophenone.