Process for preparation of chiral salbutamols.

Abstract

The present invention provides a process for the prepn. of chiral salbutamols comprising stereoselective transfer-hydrogenation of α-iminoketone. For example, 5-acetylsalicylate was oxidized to Me 5-(dihydroxyacetyl)salicylate, followed by reaction with tert-butylamine to give Me 5-[(tert-butylimino)acetyl]salicylate. The α-iminoketone obtained in the previous step was hydrogenated in the presence of (S,S)-Ru-TsDPEN or (R,R)-Ru-TsDPEN, followed by redn. of the ester group to give (R)-salbutamol or (S)-salbutamol in good yield, resp. [on SciFinder(R)]