A DFT computational study on the molecular mechanism of the nitro group migration in the product derived from 3-nitro-2-(trifluoromethyl)-2H-chromene and 2-(1-phenylpropylidene)malononitrile

• A unusual [1,5] NO2 shift in trifluoromethylated dibenzopyran systems was studied using DFT methods.
• Mechanism of nitrous acid extrusion from trifluoromethylated nitrochromenes was analysed.
• Influence of DFT level on the mechanism of [1,5] NO2 shift and nitrous acid extrusion was analysed.
• Aromatisation of dibenzopyran systems is the driving force favouring the nitrous acid extrusion.

A migration of the nitro group in the trifluoromethylated partially hydrogenated dibenzopyran system was studied using various DFT theoretical levels. It was found that this reaction proceeds via [1,5] sigmatropic shift mechanism. Subsequently competitive nitrous acid extrusion channel was analysed.

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