Cyclohexadienones. Use of the dienone–phenol rearrangement in measuring migratory aptitudes of alkyl groups

Abstract

Kinetic and product studies of the rearrangements in aqueous sulphuric acid of selected cyclohexa-2,5-dienones are used to measure the migratory aptitudes in this carbonium-ion rearrangement of the methyl, ethyl, and n-propyl groups. The rearrangement of 4a-ethyl-5.6,7.8-tetrahydronaphthalen-2(4aH)-one in aqueous sulphuric acid has been reinvestigated. It is demonstrated that the lanthanide shifts brought about by Eu(fod)₃ on the n.m.r. spectra of isomeric alkylphenols have great value in structure determination.