Enantioselective Diels-Alder reactions with left-handed G-quadruplex DNA-based catalysts

Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential functions.This study utilised it to catalyse enantioselective Diels-Alder reactions,considering its different optical rotation compared to an ordinary G4.It was determined that when L-G4 was used with a combination of copper(Ⅱ)ions,there was a good enantioselectivity(-52%ee)without further addition of ligands.When further consideration was given by adding G4 ligands,G4 was further stabilised,even obtaining a better enantioselectivity(up to-80%ee).Moreover,when using ligands that have regulatory effects on G4,the ee value can be adjusted.In this work,a minimal left-handed G4 was reported.A follow-up study was also con ducted,which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity,but is not so effective as the former case.This indicates that a complete G4 structure is relatively conducive to chiral catalysis.