Synthesis of Seleno-Dibenzocycloheptenones/Spiro[5.5]Trienones by Radical Cyclization of Biaryl Ynones

We report herein an alternative method
for the synthesis of seleno-dibenzocyclo­heptenones
and seleno-spiro[5.5]­trienones through the radical cyclization
of biaryl ynones in the presence of diorganyl diselenides, using Oxone
as a green oxidizing agent. The reactions were conducted using acetonitrile
as the solvent in a sealed tube at 100 °C. The protocol is operationally
simple and scalable, exhibits high regioselectivity, and allows the
synthesis of 24 dibenzocyclo­heptenones/spiro[5.5]­trienones in
yields of up to 99%, 17 of which are unpublished compounds. Additionally,
synthetic transformations of the prepared compounds, such as oxidation
and reduction reactions, are demonstrated.