Synthetic Studies on Damascenones

The odor principle β‐damascenone and its isomer α‐damascenone have been prepared by treatment of the corresponding ethyl safranates with excess allyl lithium followed by alkoxide catalyzed isomerization of the resulting products with β, γ‐unsaturated ketonic side chains. Addition of allyltriphenylphosphorane (preferably prepared from allyltriphenylphosphonium chloride) rather than the propenyl isomer to ethyl α‐isopropylidene‐acetoacetate produced ethyl α‐safranate. This represents a new, potentially general method for the synthesis of functionalized cyclohexadienes.