Prodn. of long-chain (Z)-9-alkenes (I) comprises first reacting acid chlorides of formula (II) with a soln. of an n-alkyl Mg halide contg. a Cd salt to give the ketones of formula (III). (III) are then reduced conventionally to (I). (n = 7-11 and p = 11-n for prodn. of tricosenes, and n = 7-9 and p = 9-n for prodn. of heneicosenes). Specifically claimed are the novel (Z)-heneicos-12-en-4-one and (Z-tricos-14-en-6-one. The (Z)-9-tricosenes and heneicosenes are components of the sex attractant of the housefly. (I) are prepd. in good yields with high stereochemical purity. Pref. (II) are derived from erucic and oleic acids since these are readily available in pure form. Reaction with the Grignard is in ether, THF, dioxan etc. and the Cd salt is pref. the anhydrous chloride, bromide or iodide used at Cd:Mg atom ration =0.5:1. The ketone is pref. reduced using a high boiling solvent (pref. glycols or glycol ethers) and solns. of alkali hydroxide and hydrazine hydrate at =100 degrees C, esp. 100-200 degrees C.
展开▼
