Formation and rearrangement of 6,6-diphenylbicyclo[3,1,0]hex-2-ene

Abstract

The role of biradical intermediates in the addition of diphenylmethylene to cyclopentadiene is discussed. The adduct 6,6-diphenylbicyclohexene is oxidised to 6,6-diphenylfulvene by N-bromosuccinimide or t-butyl peroxy-benzoate–copper. These results are reviewed in the context of cyclohexadienone photochemistry. With potassium t-pentoxide in t-pentyl alcohol the diphenylbicyclohexene is isomerised to a mixture of diphenylcyclohexadienes. With potassium t-butoxide in dimethyl sulphoxide, a mixture of benzhydrylcyclopentadienes is obtained.