High pressure -Lewis acid catalyzed diels-alder reactions of 3-methylcyclohex-2-en-1-one. A straightforward route to cis and Tras angularly methylated octalones.

By the application of high pressure in combination with EtAlCl2 as the Lewis acid, it is possible to achieve Diels-Alder reactions of 3-methylcyclohex-2-en-1-one with simple acyclic dienes. This cycloaddition offers the most straightforward route to cis and trans angularly methylated octalones, precursors in the total synthesis of terpenes and steroids.