(5S)-1-Aza-2-imino-3-oxa-4,4-diphenylbicyclo(3.3.0)octane: a novel chiral catalytic source containing the N-(C=NH)-O moiety for the borane-mediated asymmetric reduction of prochiral ketones

(5S)-1-Aza-2-imino-3-oxa-4,4-diphenylbicyclo(3.3.0)octane, a novel chiral catalytic source containing the N-(C=NH)-O moiety, has been synthesized and successfully utilized, for the first time, as a chiral catalytic source in the borane-mediated asymmetric reduction of prochiral ketones in refluxing toluene, to provide the corresponding secondary alcohols with up to 93% enantiomeric excess