N-C Axially Chiral Anilines Electronic Effect on Barrier to Rotation and A Remote Proton Brake

Yumiko Iwasaki (1) , Ryuichi Morisawa (1) , Satoshi Yokojima , Hiroshi Hasegawa , Christian Roussel (2) , Nicolas Vanthuyne (2) , Elsa Caytan (3) , Osamu Kitagawa (1)

1 Shibaura Institute of Technology
2 ISM2 - Institut des Sciences Moléculaires de Marseille
3 ISCR - Institut des Sciences Chimiques de Rennes

N-Aryl-N-methyl-2-tert-butyl-6-methylaniline derivatives exhibit a rotationally stable N-C axially chiral structure and the rotational barriers around an N-C chiral axis increased with the increase in electron-withdrawing character of para-substituent on the aryl group. X-ray crystal structural analysis and the DFT calculation suggested that the considerable change of the rotational barriers by the electron effect of para-substituents is due to the disappearance of resonance stabilization energy caused by the twisting of para-substituted phenyl group in the transition state. This structural property of the N-C axially chiral anilines was employed to reveal a new acid-decelerated molecular rotor caused by the protonation at the remote position (remote proton brake).

Keywords: amines; axial chirality; density functional calculations; electronic effect; proton brake

Domains: Chemical Sciences; Theoretical and/or physical chemistry

Yumiko Iwasaki, Ryuichi Morisawa, Satoshi Yokojima, Hiroshi Hasegawa, Christian Roussel, et al.. N-C Axially Chiral Anilines Electronic Effect on Barrier to Rotation and A Remote Proton Brake. Chemistry - A European Journal, 2018, 24 (17), pp.4453-4458. ⟨10.1002/chem.201706115⟩. ⟨hal-01771098⟩