Reaction of tetrasubstituted cyclopentadienones 1,1a with phenacyl bromide 2, dichloroacetophenone 3, ethyl bromomalonate 4, bromomethyl-p-tolylsulphone 5 in 50% NaOH and in the presence of benzyltriethylammonium chloride gave the carbene adduct 6,7,7a as well as pentasubstituted phenols 8,9,9a,10,10a,11,11a. The carbene adducts 6,7 and 7a were also converted into the phenols 8,9,9a using t-BuOK or NaOH in refluxing t-BuOH.