Fig. 3: Isomerization mechanism of cyclotriluteolin.
From: Oxygen mediated oxidative couplings of flavones in alkaline water

A Ring rearrangement of cyclotriluteolin (CTL). B Variable temperature NMR of 4a. C Proposed intramolecular ring rearrangement of cyclotriluteolin. D Calculated Gibbs free energies of cyclotriluteolin isomers. Calculations were performed at the M06-2X/6-311+G(d,p), SMD(H2O)//M06-2X/6-31G(d)SMD(H2O) level of theory. Energies are in kcal·mol−1.