Enhanced Fluorescence of 3,3′-Diformyl BINOL by Functional Secondary Amines

Although 3,3′-diformylBINOL (S)-1 shows little change in its fluorescence when treated with primary amines, its fluorescence can be greatly enhanced by using functional secondary amines including β- and γ-amino alcohols and 1,2- and 1,3-bis(secondary amine) compounds. It has been demonstrated that the functional secondary amines react with (S)-1 to convert the conjugated aldehyde groups to unconjugated oxazolidines or aminals to turn on the fluorescence.