Formal total synthesis of ent-codeinone and ent-codeine was accomplished via the total synthesis of ent-neopinone attained in 14 steps from β-bromoethylbenzene. The key steps included (i) enzymatic dihydroxylation of β-bromoethylbenzene with E. coli JM109 (pDTG601a), an organism that overexpresses toluene dioxygenase, (ii) a Heck reaction to establish C-13 stereogenic center, (iii) aldol condensation, and (iv) 1,6-conjugate addition of the ethylamino side chain to C-9. Several other modes of construction of the C-9 and C-14 centers were also investigated: Mannich cyclization, and aza-Prins reaction. The synthesis of ent-codeinone was formalized by intersecting Fukuyama’s recently published approach. Experimental and spectral data are provided for all new compounds.
通过从β-溴乙基苯合成ent-新松酮和ent-可待因的正式全合成,共进行了14步合成ent-新松酮。关键步骤包括:(i) 利用过表达甲烷二氧化酶的大肠杆菌JM109(pDTG601a)对β-溴乙基苯进行酶催化二羟基化,(ii) Heck反应以建立C-13立体异构中心,(iii) 亚醛缩合,以及(iv) 乙基氨基侧链对C-9进行1,6-共轭加成。还研究了几种其他构建C-9和C-14中心的方法:Mannich环化反应和aza-Prins反应。ent-新松酮的合成通过与福山最近发表的方法相交叉。为所有新化合物提供了实验和光谱数据。