Macrocyclization via Ring-Emitting Covalent Fixation

Significance

Replacement of the triflate counter­ions in the telechelic poly(THF) 1 with a more nucleophilic biphenyldicarboxylate by ion-exchange reaction, followed by heat treatment of complex 2 under dilution conditions (0.2 g/L), provided the covalently converted cyclic product 3 in 65% yield. The structure of 3 was confirmed by MALDI-TOF mass analysis, ¹H NMR as well as SEC characterization. These results demonstrate the effective cyclization of 2 through the ring-emitting covalent conversion by the elimination of N-phenylpiperidine units at both chain ends.