Palladium-catalysed coupling reactions based on a novel and easy-to-synthesise difluorinated organotrifluoroborate were used to assemble precursors to 6π-electrocyclisations of three different types. Electrocyclisations took place at temperatures between 90 and 240 oC, depending on the central component of the π-system; non-aromatic trienes were most reactive, but even systems which required the temporary dearomatisation of two arenyl sub-units underwent electrocyclisation, albeit at elevated temperatures. Photochemical conditions were effective for these more demanding reactions. The package of methods delivered a structurally-diverse set of fluorinated arenes, spanning a 20 kcal mol-1 range of reactivity, by a flexible route.
- electrocyclic reactions
- density functional calculations
Percy, J. M., Emerson, H., Fyfe, J. W. B., Kennedy, A. R., Maciuk, S., Orr, D., ... Wilson, P. G. (2016). Modular construction of fluoroarenes from a new difluorinated building block via cross-coupling/electrocyclisation/ dehydrofluorination reactions. Chemistry - A European Journal, 22(34), 12166-12175. https://doi.org/10.1002/chem.201601584