The Li Group @ Lanzhou University

Home » 2019 » December

Monthly Archives: December 2019

Total Synthesis of (−)-Oridonin

J. Am. Chem. Soc. 2019, 141, 20048-20052   full text link

文献汇报人:王文雪

汇报日期: 20191221

图文摘要:

2.png

  • 推荐原因:

(-)-Oridonin 为冬凌草的主要活性成分。目前人们发现它对神经保护和神经退行性疾病有潜在的应用价值。之前,人们只能通过鄂西香茶菜甲素,以半合成低收率获得(-)-Oridonin。本文作者利用the Interrupted Nazarov Reaction以及两次1,2-迁移和一系列氧化还原过程,完成它的首次全合成。其中,部分片段的合成对于其他二萜类化合物的合成也有较好的借鉴。

Chemoenzymatic Total Synthesis of ent-Oxycodone: Second‑, Third‑,and Fourth-Generation Strategies

J. Am. Chem. Soc. 2019, 141, 27, 10883-10904   full text link

文献汇报人:Hayatullah Imtiaz

汇报日期: 20191214

图文摘要:

3

  • 推荐原因:

    Four distinct approaches to ent-oxycodone were designed and accomplished. All rely on the same starting material, the diene diol derived from phenethyl acetate by the whole-cell fermentation with E. coli JM109 (pDTG601A), a strain that overexpresses toluene dioxygenase.

    The key step in the first-generation approach involves the construction of the C-9/C-14 bond by a SmI2-mediated cyclization of a keto aldehyde. The second-generation design relies on the use of the Henry reaction to accomplish this task. In both of these syntheses, Parker’s cyclization was employed to construct the D-ring. The third generation synthesis provides an improvement over the second in that the nitrogen atom at C-9 is introduced by azidation of the C-9/C-10 olefin, followed by reduction and lactam formation between the C-9 amine and the Fukuyama-type lactone. Finally, the fourth generation takes advantage of the keto−nitrone reductive coupling to generate the C-9/C-14 linkage. The four generations of the total syntheses of ent-oxycodone were accomplished in 13, 18, 16, and 11 operations (19, 23, 24, and 18 steps), respectively.

Total Synthesis of (-)-Englerin A

DOI: 10.1002/anie.200905032 full text link

文献汇报人:王建平

汇报日期: 2019127

图文摘要:

2

  • 推荐原因:

Englerin A是之前的一个明星分子,具有很好的抗肾癌活性,世界范围内有很多课题组用各种策略对它进行了全合成,例如有RCM构建骨架、金催化一步构建骨架以及二碘化钐自由基构环等,本次通过对比学习其中七个课题组的工作,体会不同策略的优劣。

Total Synthesis of (-)-Daphenylline

DOI: 10.1002/anie.201902268  full text link

文献汇报人:李慧

汇报日期: 20191130

图文摘要:

1.png

  • 推荐原因:

虎皮楠生物碱( Daphniphyllum alkaloids )是一大类从虎皮楠属植物中分离得到的生物碱的总称,由于复杂多变的骨架特征,其吸引了大量合成研究小组的兴趣。邱发洋课题组以(S)-Carvone作为手性源,通过设计全新的合成策略,以19步(分离纯化步骤)及7.6%的总产率实现了(-)-Daphenylline的不对称全合成。该全合成路线使手性得到极好的控制并成为目前该分子的全合成中反应步骤最少、产率最高的路线。此外,部分中间体可通过扩环合成虎皮楠生物碱家族的其他骨架。该研究成果的亮点在于以价廉易得的天然手性源(S)-Carvone为起始原料,运用简单的合成砌块,以极好的立体选择性,简洁、高效地实现了(-)-Daphenylline的全合成。关键步骤包括Mg(ClO4)2催化的酰胺环化, Diels-Alder 环加成反应,Robinson环化/芳构化,Friedel-Crafts环化。