Catalytic effects of Lewis acids on 1,3-DC reaction: A luminescent study

► A fluorescence study of catalytic effect of an 1,3-DC reaction between an acyclic nitrone (N1) with two different dipolarophiles D1 and D2 in toluene. ► Yb3+ quenches the fluorescence intensity of N1 more efficiently than Li+. ► Li+ shows better interaction with both the two dipolarophiles D1 and D2 hence can accelerate the 1,3-DC reaction rate between N1 and D. ► Yb3+ can only be used as good catalyst for the 1,3-DC reaction between N1 and D2. ► Spectroscopic findings are rationalized with DFT calculated electrophilicity indices of the reactants.