Photoaddition of allenes to p-quinones

Abstract

p-Benzoquinone, 2-methyl-p-benzoquinone, tetrachloro-p-benzoquinone, and 1,4-naphthoquinone undergo photochemical addition to tetramethyl- or 1,1-dimethyl-allene to form 5-hydroxyindan-2-one derivatives. The kinetics of the photoaddition of p-benzoquinone to tetramethylallene was investigated by quantum yield measurements in the absence and presence of anthracene, and the rate of addition of triplet p-benzoquinone to tetramethylallene was estimated. A mechanism is proposed involving addition and rearrangement.