Kinetics of the dienone–phenol rearrangement of some 4,4-dimethylcyclohexa-2,5-dienones

Abstract

The kinetics of the dienone–phenol rearrangements of 4,4-dimethyl-, 3,4,4-trimethyl-, 3-ethyl-4,4-dimethyl-, 2,4,4,5- and 3,4,4,5-tetramethyl-, and 3,5-diethyl-4,4-dimethylcyclohexa-2,5-dienones have been measured in sulphuric and perchloric acid solutions at 25°C, and the products identified. The reaction is interpreted in terms of an A 1 mechanism, and allows the transition state acidity function behaviour to be determined. The effects of substitution on the rates of rearrangement are discussed.