Access to 5‐Substituted 3‐Aminofuran/Thiophene‐2‐Carboxylates from Bifunctional Alkynenitriles
摘要:
AbstractAn atom‐economical approach for the synthesis of 3‐aminofurans/thiophenes via a conjugate addition of alcohols and thiols with electron withdrawing groups (EWGs) at α positions on alkynenitriles followed by a modified Thorpe‐Ziegler cyclization have been reported. This operationally simple protocol offers a rapid access to a library of 3‐aminofurans/thiophenes in moderate to good yields.magnified image
An aerobic and green C–H cyanation of terminal alkynes
作者:Peng-Fei Zhu、Yi-Xin Si、Song-Lin Zhang
DOI:10.1039/d0ob01928c
日期:——
C–H cyanation of terminal alkynes with α-cyanoesters serving as a nontoxic cyanide source. In situ generation of the key copper cyanide intermediate is proposed by a sequence of α-C–H oxidation and copper-mediated β-carbon elimination of α-cyanoesters, releasing the α-ketoester byproduct observed experimentally. The ensuing reaction of copper cyanide with terminal alkynes delivers preferentially cyanoalkynes
本研究描述了末端炔烃的良性 C-H 氰化,其中 α-氰酸酯作为无毒氰化物源。关键氰化铜中间体的原位生成是通过一系列 α-C-H 氧化和铜介导的 β-碳消除 α-氰酸酯,释放实验观察到的 α-酮酯副产物提出的。随后的氰化铜与末端炔烃的反应优先提供氰基炔烃,并超过了末端炔烃可能的 Glaser 型二聚或在质子条件下不希望的 HCN 积累。共氧化剂 K 2 S 2 O 8的存在对这种选择性至关重要,可能是通过促进氧化转移金属化和由此形成的 Cu(III )(乙炔化物)(CN)中间体。使用的所有试剂和盐都是可商购的,便宜且无毒,避免使用氰化研究中通常需要的剧毒氰化物盐。该反应的范围用一组炔烃和 α-氰酸酯来证明。将该方法应用于雌酮衍生物末端炔基的后期功能化也是可行的,显示出其在药物设计中的实用价值。
Copper-catalyzed direct cyanation of terminal alkynes with benzoyl cyanide
作者:Yan Du、Zheng Li
DOI:10.1016/j.tetlet.2018.11.049
日期:2018.12
Copper-catalyzed direct cyanation of terminal alkynes is achieved using less toxic, stable and easy to handle benzoylcyanide as a cyanide source and air as an oxidant. This protocol provides a good alternative to the preparation of 3-arylpropiolonitriles under mild condition.
Ionic Liquid-Mediated One-Pot 3-Acylimino-3<i>H</i>-1,2-dithiole Synthesis from Thiocarboxylic Acids and Alkynylnitriles via In Situ Generation of Disulfide Intermediates
作者:Chandresh Kumari、Avijit Goswami
DOI:10.1021/acs.joc.2c00301
日期:2022.7.1
derivatives via a metal-free annulationreaction of alkynylnitriles with thiocarboxylic acids mediated by ionic liquids [BMIM]Br has been reported. This operationally simple protocol offers an easy and rapid access to a library of dithiol derivatives in moderate to good yields. The mechanistic studies show a benzoyldithio anion addition to alkynylnitriles followed by an annulationreaction through the involvement
已经报道了一种实用且直接的策略,用于通过离子液体 [BMIM]Br 介导的炔基腈与硫代羧酸的无金属环化反应合成 3-acylimino-3 H -1,2-dithiol 衍生物。这种操作简单的协议提供了一种以中等至良好的产量轻松快速地访问二硫醇衍生物库的方法。机理研究表明,苯甲酰二硫代阴离子加成到炔基腈中,然后通过作为关键中间体的二硫化物部分参与环化反应。
Copper mediated oxidative coupling between terminal alkynes and CuCN
作者:Yihang Li、Dunfa Shi、Pengqi Zhu、Hongxing Jin、Shuo Li、Feng Mao、Wei Shi
DOI:10.1016/j.tetlet.2014.11.108
日期:2015.1
A direct oxidative cross coupling between terminal alkynes and CuCN to form 1-cyanoalkynes was reported. FeCl3 was employed as the sole additive. The reaction could be carried out under mild conditions, with moderate to good yields. (C) 2014 Published by Elsevier Ltd.
Silver-Mediated Direct C–H Cyanation of Terminal Alkynes with <i>N</i>-Isocyanoiminotriphenylphosphorane
作者:Hannan Wang、Pengbing Mi、Wanjun Zhao、Ravi Kumar、Xihe Bi
DOI:10.1021/acs.orglett.7b02743
日期:2017.10.20
A direct cyanation of terminal alkynes for the synthesis of propionitrile derivatives, with the aid of silver salt using water additive, has been achieved. The cyano source used is N-isocyanoiminotriphenylphosphorane, which is nontoxic, safe, and easy to handle. This protocol is characterized by its operational simplicity, high efficiency with excellent yields, broad substrate scope, and greater functional group tolerance.