Mandava Suresh, Koo Jaun, Hwang Jungjoong, Nallapaneni Hari Krishna, Park Haeil, Lee Jongkook
Pharmaceutical Chemistry Laboratory, College of Pharmacy, Kangwon National University, Chuncheon, South Korea.
Front Chem. 2020 Jun 30;8:494. doi: 10.3389/fchem.2020.00494. eCollection 2020.
The cross-metathesis (CM) of methallyl halides catalyzed using four different ruthenium-based complexes-Grubbs catalyst, Grubbs second-generation catalyst, Hoveyda-Grubbs second-generation catalyst, and Stewart-Grubbs catalyst-was investigated. When methallyl chloride or bromide was reacted with a model substrate containing a benzyl ether group, the Grubbs catalyst, and Grubbs second-generation catalyst did not promote the reaction well. However, the Hoveyda-Grubbs second-generation catalyst and Stewart-Grubbs catalyst afforded the corresponding products in moderate to good yield with moderate / selectivity. Accordingly, several functionalized methallyl halides were prepared by CM. Various functional groups were well-tolerated in this system when the Stewart-Grubbs catalyst was used. To demonstrate the practical utility of our method, methallyl halide CM was successfully employed for the formal total synthesis of a natural product (-)-presphaerene, in which the precursor of the key cyclopentanecarboxylate intermediate was efficiently prepared in three steps.
研究了使用四种不同的钌基配合物（格拉布催化剂、格拉布第二代催化剂、霍维达-格拉布第二代催化剂和斯图尔特-格拉布催化剂）催化的甲基烯丙基卤化物的交叉复分解反应（CM）。当甲基烯丙基氯或溴与含有苄醚基团的模型底物反应时，格拉布催化剂和格拉布第二代催化剂不能很好地促进反应。然而，霍维达-格拉布第二代催化剂和斯图尔特-格拉布催化剂以中等至良好的产率和中等/选择性得到了相应的产物。因此，通过CM制备了几种官能化的甲基烯丙基卤化物。当使用斯图尔特-格拉布催化剂时，该体系对各种官能团具有良好的耐受性。为了证明我们方法的实际应用价值，甲基烯丙基卤化物CM成功地用于天然产物（-）-前球烯的形式全合成，其中关键的环戊烷羧酸酯中间体的前体通过三步高效制备。
