Reactions of 1-Oxaspiro[2.5]octa-5,7-dien-4-ones with nucleophiles

Abstract

The 1-oxaspiro[2.5]octa-5,7-dien-4-ones (6-spiroepoxy-2,4-cyclohexadienones) (7) on reaction with a number of carbon, nitrogen, oxygen and halogen nucleophiles produced a variety of interesting substitution and rearrangement products (8)-(19) in moderate yields. The products derived almost exclusively from initial attack of the nucleophile with either the secondary or quaternary carbon of the epoxy ring and these various modes of reaction of the spirocyclic system are discussed. The formation of ortho-substituted phenols from the 1-oxaspiro[2.5]octa-5,7-dien-4-ones suggests that the latter structures may be regarded as polarity-reversed masked phenols. Tropolones, products of a possible ring-expansion reaction, were not observed in any of the reactions investigated.