To extend the synthetic potential of trifluoromethyl-substituted semisquarate (CF3-semisquarate) previously synthesized by us as a pluripotent building block, its electrophilic derivatization was investigated. The electrophilic addition of allylic silanes and silyl enolates to CF3-semisquarate afforded the corresponding 4-hydroxycyclobutenones. Subsequent ring expansion of these products via thermolysis or oxidation using lead tetraacetate afforded trifluoromethylated bicyclo [3.2.0] heptenones or (Z)-gamma-alkylidenetetronates.