A Fluorogenic Aldehyde Bearing a 1,2,3-Triazole Moiety forMonitoring the Progress of Aldol Reactions

摘要

We have developed a new type of fluorogenic aldehyde bearing a 1,2,3-triazole moiety that is useful formonitoring the progress of aldol reactions through an increase in fluorescence. Whereas 6-methoxy-2-naphthaldehyde was highly fluorescent, the fluorogenic aldehyde, 4-formylbenzene connected to the6-methoxy-2-naphthyl group through a 1,2,3-triazole moiety, was essentially nonfluorescent in aqueoussolutions. We suggest that the 4-formylphenyl group acts as a quencher to suppress the fluorescence ofthe 6-methoxy-2-naphthyltriazole moiety. The product of the aldol reaction of this aldehyde does nothave a quenching moiety and showed more than 800-fold higher fluorescence than the aldehyde. Assaysystems using the fluorogenic aldehyde were validated by screening of aldol catalysts, ranking of theactivities of the catalysts, and evaluation of reaction conditions.