Generation, Observation, and Free Radical Reactivity of Aliphatic Bisketenes:  The Solution to a Long-Standing Problem

Bisketenes OCCH(CH₂)_nCHCO (1b,c,d, n = 4, 3, 6) and (E)-OCCHCHCHCHCO (E-13) were generated in solution by dehydrochlorination of bis(acyl chlorides) and by photochemical Wolff rearrangements and identified by their characteristic IR signals. The bisketenes react with aminoxyl radicals to give tetraaddition products for 1b and conjugate 1,6-diaddition for E-13.