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 (SeCHCl)-controlled molecular rotor having a Cl-Pd-Cl rotor spoke attached onto a Se-Pd-Se axle. NMR data acquired at various temperatures established ΔG‡298K/ΔG‡350K values of 15.5 and 17.2 kcal mol-1 for a roughly 4.5 Å-long rotor. The molecular rotor showed excellent catalytic activity with reverse regioselectivity for annulation of 2-arylimidazo[1,2-a]pyridines (yields: ∼53-78%) with only 1.5 mol% catalyst loading.