Chiral Bis(8-Quinolyl)Ethane-Derived Diimine: Structure Elucidation and Catalytic Performance in Asymmetric Synthesis of (S)-Warfarin

C2-symmetric diimine generated in situ from (R,R)-HPEN and 8-formylquinoline was readily transformed to novel chiral pre-III bearing 1(S),2(S)-bis(quinolin-8-yl) ethane salicylic aldehyde fragments via stereoselective diaza-Cope rearrangement. The structure absolute configuration of the product established by X-ray diffraction study corresponding Rh(III) complex. In presence pre-III, practically important enantioselective reactions 4-hydroxycoumarin with α,β-enones afforded anticoagulant (S)-warfarin its derivatives aqueous THF high yield (88–92%) enantioselectivity 85–93% ee.