Moulting hormones of insects and crustaceans: The synthesis of 22-deoxycrustecdysone

A partial synthesis of the title compound (III) has been accomplished from crustecdysone (I). Chromic acid oxidation of crustecdysone afforded the ketone (VI) which was converted into the corresponding acetonide silyl ether (IX). Alkylation of (IX) with the Grignard reagent from (XI) and hydrolysis of the protecting groups afforded the required compound (III). An alternative route which facilitates tritium labelling afforded the same product. The biological activity and spectral properties of the product are discussed.