J. Clayden et al., (S)-2-(DIBENZYLAMINO)-3-PHENYLPROPANAL AS A CHIRAL AUXILIARY - A NEW STRATEGY FOR THE ASYMMETRIC-SYNTHESIS OF 2-SUBSTITUTED ALCOHOLS, Tetrahedron : asymmetry, 9(8), 1998, pp. 1427-1440
The high levels of 1,2-stereocontrol observed in nucleophilic addition
s to (S)-2-(dibenzylamino)-3-phenylpropanal (available in three high-y
ielding steps from L-phenylalanine) can be converted to remote 1,4-ste
reocontrol by a stereospecific rearrangement if the nucleophile is a v
inyl anion equivalent. Ozonolysis of the product followed by reductive
work-up returns an enantiomerically pure 2-substituted alcohol, along
with the (S)-2-(dibenzylamino)-3-phenylpropan-1-ol precursor to the s
tarting aldehyde, which functions as a chiral auxiliary. The sequence
provides a new strategy for the use of aldehydes as chiral auxiliaries
in the synthesis of chiral alcohols bearing oxygen-or carbon-based 2-
substituents. (C) 1998 Elsevier Science Ltd. All rights reserved.