A Complete Gear System in N-Benzoyl-Carbazole Derivatives
摘要:
2',6'-Disubstituted N-benzoylated carbazole derivatives were found to exhibit atropisomerism. The bulky substituents restricted rotation about the N-C7' and C7'-C1' bonds to separate four atropisomers, in which rotation about the C7'-C1' bond was in perfect concert with rotation about the N-C7' bond. Complete geared rotation without slippage at 37 degrees C for 7 days was observed for the first time. Conformational analysis clarified the preference for the gear system over other internal conversion pathways.