Carbonyl Chemistry of Tetrafluorocyclopentadienone

Article abstract of DOI:10.1021/jo00001a032

In order to control the Diels-Alder reactivity of the very labile title compound 1, experiments designed to modify the carbonyl group have been carried out.With methanol a hemiketal (4) is formed reversibly at low temperatures, but conjugate addition to give 3-methoxy derivatives 5 and 6 occurs at ordinary temperatures.Diazomethane reacts with 1 in cold methanol to give a spirooxirane (9) which undergoes Diels-Alder dimerization orders of magnitude slower than dienone 1 at room temperature.Hydrogen cyanide gives a cyanohydrin (15) with 1 at low temperatures, but the compound decomposes at 0 deg C.Trimethylsilyl cyanide yields the trimethylsilyl cyanohydrin 16, a stable derivative of 1 that dimerizes only at elevated temperatures, yet retains reactivity as a Diels-Alder diene.