A Facile Synthesis of 9-Nor-9-hydroxyhexahydrocannabinol via Intramolecular Reverse Electron Demand Diels-Alder Cyclization

A simple and efficient new synthesis of 9-nor-9-hydroxyhexahydrocannabinol is achieved, through the intramolecular [4+2] cycloaddition of an o-quinonemethide which is generated from 2-(1-hydroxy-3-methoxymethoxy-7-methyl-6-octenyl)-1,3-bis(O-methoxymethyl)olivetol (12b), which in turn is prepared by reaction of the lithiated olivetol bis(methoxymethyl)ether with 3-methoxymethoxy-7-methyl-6-octenal (9)