Regioselective addition of DDQ on a quinoid ring: an entry into chiral zwitterionic bridging ligands

Gabriel Canard (1) , Zhongrui Chen (1) , Aprilliyani Suryaningtias (1) , Marion Jean (2) , Nicolas Vanthuyne (2) , Michel Giorgi , Christian Roussel (3) , Olivier Siri (1)

1 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
2 ISM2 - Institut des Sciences Moléculaires de Marseille
3 ChiroSciences

The regioselective insertion of DDQ into a C-H bond of the 6π + 6π electron zwitterionic benzoquinonemonoimines 4a-c results in the formation of the novel chiral C-substituted quinoid ligands 11a-c. These Michael adducts feature a preserved zwitterionic form and a quaternary stereogenic carbon center as evidenced by the single crystal X-ray structure of the derivative 11a. The ECD spectra, optical rotations and racemization barriers of the two enantiomers of 11a were measured subsequently to their separation by a preparative chiral HPLC. Because the racemization of 11a is stopped in basic media, compounds 11a-c give a new entry in chiral zwitterionic bridging ligands.

Domaines: Chimie de coordination

Gabriel Canard, Zhongrui Chen, Aprilliyani Suryaningtias, Marion Jean, Nicolas Vanthuyne, et al.. Regioselective addition of DDQ on a quinoid ring: an entry into chiral zwitterionic bridging ligands. New Journal of Chemistry, 2018, 42 (10), pp.8247-8252. ⟨10.1039/c7nj03765a⟩. ⟨hal-02460761⟩