Fig. 1. (A) Oxa-Pictet–Spengler reaction of 1a and 2a; (B) conversation and yield profile for the examination of HPAs catalysts (DCE as solvent, Table S1†); (C) conversation and yield profile for the optimization of the reaction solvents (H3PMo12O40 as catalyst, Table S2†); (D) conversation and yield profile for the examination of HPAs-based ionic liquids (DMC as solvent, Table S3†) (yields were determined by GC using biphenyl as an internal standard).
