(5S)-1,3-Diaza-2-imino-3-phenylbicyclo[3.3.0]octane: first example of guanidine based in situ recyclable chiral catalytic source for borane-mediated asymmetric reduction of prochiral ketones

Abstract

(5S)-1,3-Diaza-2-imino-3-phenylbicyclo[3.3.0]octane has been synthesized and successfully employed, for the first time, as a chiral catalytic source for the borane-mediated asymmetric reduction of prochiral α-halo ketones to provide the corresponding secondary alcohols in high enantiomeric purity. The potential of this guanidine as an in situ recyclable chiral catalytic source for the borane-mediated chiral reduction processes has also been demonstrated. © 2006 Elsevier Ltd. All rights reserved.