Synthetic Approaches to Caryophyllene

Starting respectively from 2-methylcyclohexanone and 2-methylcycloheptanone, a synthetic route to 8- and 9-membered carbocycles has been developed via the bicyclo-[3:3:1]-nonane and bicyclo-[4:3:1]-decane systems. In particular, 1-methyl-5-methylenecyclooct-l-ene and l-methyl-5-methylenecyclonon-l-ene have been synthesised as models for a projected synthesis of caryophyllene. Alternative routes to certain intermediates have been investigated to establish the most direct and conservative approach to olefins of this type, and the purity of the products has been established by spectroscopic methods. An attempt has been made to extend these methods to a synthesis of isocaryophyllene