Organozinc-aided, HMPA-free, stoichiometric three-component coupling for the general synthesis of prostaglandins and stable prostacyclin analogs with biological significance
作者:Hiroko Koyama、Atsuto Izumiseki、Masaaki Suzuki
DOI:10.1016/j.tetlet.2019.04.037
日期:2019.5
method afforded protected 5,6-didehydro-PGE2, a common intermediate for the general synthesis of natural PGs and the stable artificial prostacyclin (PGI2) analog isocarbacyclin in 88% yield. The utility of the method was further applied to the syntheses of novel intermediates, which are useful for the straightforward synthesis of 15R-TIC and 15-deoxy-TIC in 79% and 86% yield, respectively.
通过结合二甲基锌辅助的ω-侧链乙烯基锂与(R)-4-羟基-的二甲基锌辅助共轭加成反应,开发了一种三组分偶联程序,以在无HMPA和化学计量条件下构建整个前列腺素(PG)骨架。2-环戊烯酮和用α-侧链炔丙基三氟甲磺酸酯直接捕获所得的烯醇化物。二甲基锌可有效调节共轭加成和炔基化反应。因此,该方法提供了受保护的5,6-didehydro-PGE 2,这是天然PG和稳定的人工前列环素(PGI 2的一般合成的通用中间体)类似异卡巴环素,收率88%。该方法的实用性进一步应用于新型中间体的合成,这些中间体可分别以79%和86%的收率直接合成15 R -TIC和15-脱氧-TIC。
Cobalt-Catalyzed Markovnikov Selective Sequential Hydrogenation/Hydrohydrazidation of Aliphatic Terminal Alkynes
作者:Jieping Chen、Xuzhong Shen、Zhan Lu
DOI:10.1021/jacs.0c07258
日期:2020.8.26
pot. A cobalt hydride species was employed as two roles for both a unique metal-catalyzed Markovnikov-type insertion of the aliphatic terminal alkynes and then metal-catalyzedhydrogen atom transfer of alkenes. This operationally simple protocol exhibits excellent functional group tolerance and step economy. The hydrazone products could be easily transferred to various valuable amine derivatives.
Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes
作者:Zhaoyang Cheng、Shipei Xing、Jun Guo、Biao Cheng、Lan‐Fang Hu、Xing‐Hong Zhang、Zhan Lu
DOI:10.1002/cjoc.201900079
日期:2019.5
aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem‐Bis(dihydrosilyl)alkanes containing four silicon‐hydrogen bonds are efficiently constructed in an atom‐economical manner. Tolerated substrates include simplest alkyne‐ethyne, a complicated drug derivative and various functionalized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved
Cobalt-Catalyzed Asymmetric Synthesis of gem-Bis(silyl)alkanes by Double Hydrosilylation of Aliphatic Terminal Alkynes
作者:Jun Guo、Hongliang Wang、Shipei Xing、Xin Hong、Zhan Lu
DOI:10.1016/j.chempr.2019.02.001
日期:2019.4
value in asymmetric synthesis, functional materials, and medicinal chemistry. Compared with single-silyl compounds, bis(silyl) ones are understudied because of the lack of the efficient synthetic protocols. The development of efficient synthetic approaches to access bis(silyl) compounds is highly desirable for studying their basic properties and potential utilities. Here, a cobalt-catalyzed sequential