Novel Synthesis of 5,5-Dimethyl-1-octalin Derivatives

Article abstract of DOI:10.1021/jo00147a010

Pyrolysis of 3-isopropenyl-2-allylcyclohex-2-en-1-one (4) at ca. 275 deg C yielded 3,4,5,6-tetrahydro-5,5-dimethyl-1(2H)-naphthalenone (1) as the chief product.Higher pyrolysis temperatures also yielded methyl substituted α-tetralones derived from 1.Reductive methylation of 1 gave the trans-angularly methylated derivative 9 as the only product.The dienolate intermediate in this transforamtion was also trapped as a trimethyl ether, 8.Mechanisms for the pyrolytic rearrangement and the reductive alkylation are discussed.