CHIRAL RECOGNITION OF TARTARIC ACID DERIVATIVES WITH CHROMENONE-BENZOXAZOLE RECEPTORS AND A SPIROBIFLUORENE SPACER

Abstract The combination of a spirobifluorene spacer with two chromenone-amino-benzoxazole binding arms affords a chiral cleft type receptor. Due to the strong chiral recognition, resolution of the receptor racemic mixture can be achieved by means of a silica gel TLC plate impregnated with optically pure dibenzoyl tartaric acid. Slow complex formation on the 1 H-NMR scale with this host at −10°C allows observation of different signals for free and complex guests in 1 H-NMR.