Carbene-Catalyzed Activation of 2-Aminobenzaldehyde for Access to Chiral Fluorescent Quinazolinone.

A carbene-catalyzed reaction to synthesize a chiral quinazolinone with a new activation mode of an "aniline-like" N-H moiety is disclosed. Addition of the nitrogen atom of diphenyl o-aminobenzaldehydes via NHC activation to imines leads to chiral quinazolinones with high yields and optical purities. The acidity of the N-H moiety was extremely increased through the formation of an acyl azolium intermediate, which was investigated by DFT calculations. Moreover, the chiral quinazolinones were found to have high fluorescence quantum efficiency.