Highly enantioselective Strecker reaction of ketoimines catalyzed by an organocatalyst from (S)-BINOL and L-prolinamide

A study was conducted to propose a new kind of N,N'-dioxide with an axial chirality for the enantioselective cyanation of N-Ts-protected ketoimine. The study assumed that the stereocontrol will be enhanced, by employing a suitable chiral linker. The new kind of N,N'-dioxide catalyst was designed from BINOL and prolinamide, based on the assumption. (S)-BINOL was formylated through three steps, to afford A1 which was subjected to the condensation reaction with L-prolinamide. The study also involved the oxidation of B1, to achieve the desired novel N,N'-dioxide catalyst design. The absolute configuration of the newly formed chiral center in catalyst 1a was identified as R, based on the observation of strong NOE signal between H1 and H2.