Ir-Catalyzed Regio- and Enantioselective Hydroalkynylation of Trisubstituted Alkene to Access All-Carbon Quaternary Stereocenters
作者:Su-Lei Zhang、Wen-Wen Zhang、Bi-Jie Li
DOI:10.1021/jacs.1c04493
日期:2021.6.30
substrate-directed, iridium-catalyzed enantioselective hydroalkynylations of trisubstituted alkenes to form an acyclic all-carbon quaternary stereocenter β to a nitrogen atom. The hydroalkynylation of enamide occurred with unconventional selectivity, favoring the more hindered reaction site. Homopropargyl amides with β-stereocenters were prepared in high regio- and enantioselectivities. Combined experimental and
Synthesis of Quaternary Carbon Stereogenic Centers by Diastereoselective Conjugate Addition of Boron-Stabilized Allylic Nucleophiles to Enones
作者:Michael Z. Liang、Simon J. Meek
DOI:10.1021/jacs.0c03900
日期:2020.6.3
A method for the site- and diastereoselectiveconjugateaddition of boron-stabilized allylic nucleophiles to α,β-unsaturated ketones is disclosed. Transformations involve easily prepared γ,γ-disubstituted allyldiboron reagents, and proceed in the presence of a fluoride activator at 80 °C. Reactions proceed with a wide variety of enones and allyldiboron reagents efficiently to deliver ketone products
公开了一种将硼稳定的烯丙基亲核试剂位点和非对映选择性共轭加成到 α,β-不饱和酮的方法。转化涉及易于制备的 γ,γ-二取代烯丙基二硼试剂,并在 80 °C 下在氟化物活化剂存在下进行。反应与各种烯酮和烯丙基二硼试剂一起有效地进行,以提供含有其他难以接近的邻位 β-叔和 γ-季碳立体中心以及烯基硼部分的酮产品。该方法的实用性通过多种转化得到强调,包括交叉偶联和碳环化。
A novel total synthesis of the bioactive poly-substituted carbazole alkaloid carbazomadurin A
A new total synthesis of the neuronal cell-protecting carbazole alkaloid carbazomadurin A is described. The key step was an allene-mediatedelectrocyclicreaction involving an indole [b]-bond for the construction of a highly substituted carbazole ring. The E-alkenyl side chain at the C1 position of carbazole was introduced between O-triflate and alkenyl pinacol borate using the Suzuki–Miyaura reaction
描述了神经细胞保护咔唑生物碱咔唑马杜林A的新的全合成。关键步骤是用于构建高度取代的咔唑环的涉及吲哚[ b ]键的异戊二烯介导的电环反应。使用Suzuki–Miyaura反应,将咔唑C1位置的E-烯基侧链引入O-三氟甲磺酸盐和烯基频哪醇硼酸酯之间。用TBAF裂解SEM组,并还原甲酰基以提供carBAzomadurin A.
First total synthesis of the neuronal cell protecting carbazole alkaloid carbazomadurin A by sequential transition metal-catalyzed reactions
作者:Hans-Joachim Knölker、Jan Knöll
DOI:10.1039/b301979a
日期:2003.4.30
The highly oxygenated neuronal cell protecting carbazole alkaloid carbazomadurin A was synthesized in nine steps and 11% overall yield from isovanillic acid.