The stepwise oxidation of indolino[2,1-b]oxazolidine derivatives

• Original strategy to modulate the electrochemical properties of the indolino[2,1-b]oxazolidine core.
• Study of the stepwise oxidation via cyclic voltammetry and spectroelectrochemistry.
• Confirmation of oxidation process by electrochemical simulations.

This work presents an original strategy to modulate the electrochemical properties of the indolino[2,1-b]oxazolidine core appropriately substituted in position 5 (para-substitution of the phenyl ring) by acceptor or donor groups (CHO, OMe, Me, F, H, Cl, Br). Supported by spectroelectrochemical experiments and confronted to electrochemical simulations, the stepwise oxidation of indolino[2,1-b]oxazolidine derivatives involves an electrochemical mechanism which depends on the para-substitution of the phenyl ring and leads to either the formation of a stable radical cation, the opening of the oxazolidine ring or an irreversible aryl C–C coupling.