以间异丙基溴苯 1为起始原料 ,通过进攻环氧乙烷及溴代两步制得溴化物 3.溴化物 3与 Hagemann′s酯发生偶联反应 ,水解后生成偶联产物 5 .再以路易斯酸 BF3 ·Et2 O催化化合物 5进行分子内环化为关键步骤得到反式稠合中间体 6 ,最后通过与三苯基膦碘甲烷季盐发生 Wittig反应及氧化 ,合成了 (± ) -1 9-去甲基 -4 (1 8) ,8,1 1 ,1 3-四烯 -松香烷 -7-酮 [1 9-nor-abieta-4 (1 8) ,8,1 1 ,1 3-tetraen-7-one](8) . Starting with m-isopropylbromobenzene 1, the bromide was obtained by two steps of attacking ethylene oxide and bromine. Coupling reaction of bromide 3 with Hagemann’s ester resulted in the formation of coupled product 5 The Lewis acid BF3 · Et2 O catalyzed intramolecular cyclization of compound 5 is the key step to obtain trans-fused intermediate 6. Finally Wittig reaction and oxidation with triphenylphosphine methyl iodide methane quaternary salt to synthesize ( ± 1 -9-desmethyl-4 (1 8), 8,1 1 1,3-tetraene-eicosate-7-one 1, 13-tetraen-7-one] (8).