Highly enantioselective α‐cyanation with 4‐acetylphenyl cyanate

A highly effective asymmetric version of α-cyanation of β-keto esters and amides has been developed with Lewis acid catalyst. Thus, using 10 mol% of the tridentate bisoxazoline-zinc(II) complex as the catalyst, a series of chiral nitriles containing a quaternary carbon center have been achieved in excellent enantioselectivities up to 97% ee and up to 95% yield in the presence of 4 A MS at room temperature. For the first time, the mild active 4-acetylphenyl cyanate was used instead of cyano-hyperiodinate as the cationic cyano source in the catalytic asymmetric α-cyanation reaction.