Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A highly efficient synthesis of both enantiomers of warfarin Ia and Ib has been developed by using a novel two step “chiral switch” strategy and a DuPHOS-Rh(I) catalyzed asymmetric hydrogenation. ... A highly efficient synthesis of both enantiomers of warfarin Ia and Ib ...