Poly(ethylene glycol)-supported chiral pyridine-2,6-bis(oxazoline): synthesis and application as a recyclable ligand in Cui-catalyzed enantioselective direct addition of terminal alkynes to imines

Pyridine-2,6-bis(oxazoline) immobilized on a soluble support, viz., poly(ethylene glycol) methyl ether with M_n = 5000 Da, has been synthesized for the first time. The efficiency of its application as a chiral ligand in Cuⁱ-catalyzed direct addition of terminal alkynes to imines and the feasibility of its recycling at least in three cycles have been shown.