A selenium-coordinated palladium(ii)trans-dichloride molecular rotor as a catalyst for site-selective annulation of 2-arylimidazo[1,2-a]pyridines

This report describes the synthesis of a new class of secondary interaction (SeCHMIDLINE HORIZONTAL ELLIPSISCl)-controlled molecular rotor having a Cl-Pd-Cl rotor spoke attached onto a Se-Pd-Se axle. NMR data acquired at various temperatures established Delta G double dagger 298K/Delta G double dagger 350K values of 15.5 and 17.2 kcal mol(-1)for a roughly 4.5 angstrom-long rotor. The molecular rotor showed excellent catalytic activity with reverse regioselectivity for annulation of 2-arylimidazo[1,2-a]pyridines (yields: similar to 53-78%) with only 1.5 mol% catalyst loading.