OXAZABOROLIDINES AND DIOXABOROLIDINES IN ENANTIOSELECTIVE CATALYSIS

Enantioselective ketone reductions, allyl additions, and Diels-Alder reactions [for example Eq. (a)] are only a few of the reactions catalyzed by chiral oxazaborolidines and dioxaborolidines, which are sometimes produced in situ. A further application is described by Bringmann and Hartung on p. 761. They used adducts of oxazaborolidines and BH3 for the atropoenantioselective ring opening of lactones to obtain rotationally hindred biaryls. These are also becoming more and more important as chiral auxiliaries.