作者:Matthew M. W. McLachlan、Patrick D. O'Connor、Kelly A. Fairweather、Anthony C. Willis、Lewis N. Mander
DOI:10.1071/ch10056
日期:——
The synthesis of alkaloid GB 13 (4), isolated from the North Australian rain forest tree Galbulimima belgraveana is described. Birch reductive alkylation of 2,5-dimethoxybenzoic acid by 3-methoxybenzyl bromide, followed by an acid-catalyzed cyclization was used to synthesize the [3.3.1]bicyclononane 12. Ring contraction performed on the diazoketone 19 followed by a Diels–Alder reaction generated a
描述了从北澳大利亚雨林树Galbulimima belgraveana分离的生物碱GB 13(4)的合成。通过3-甲氧基苄基溴对2,5-二甲氧基苯甲酸进行桦木还原烷基化,然后进行酸催化的环化反应,以合成[3.3.1]双环壬烷12。对重氮酮19进行环收缩,然后进行Diels-Alder反应,生成五环中间体34碳骨架与目标生物碱极为相似。通过用锂和液氨处理,除去了Diels–Alder反应中活化和区域选择性所需的多余腈取代基。芳香环的桦木还原可以同时进行,得到二烯38,因此烯酮41通过Eschenmoser断裂被裂解。在天然产物中发现的哌啶环是通过对衍生自炔基酮48的双肟49进行还原环化而形成的,并将所得物质进一步精制为GB 13。