Cinchona-Based Primary Amine Catalyzed a Proximal Functionalization of Dienamines: Asymmetric α‑Fluorination of α‑Branched Enals

Fluorination of dienamines generated by α-branched enals and 6′-hydroxy-9-amino-9-deoxy-epi-quinidine (30 mol %) with NSFI show excellent α-regioselectivity to construct allylic fluorides containing a highly stereocontrolled quaternary fluorinated carbon (E/Z ≥ 20/1 and up to 93% enantiometric excess (ee)). By DFT calculation, the quinuclidine moiety of the catalyst was shown to function as a coordinating group to promote a reaction at the proximal α-position, and the nonclassical CH hydrogen bond plays an important role in the high enantioselectivity.