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。
Synthesis of (Z)-3-aryloxy-acrylonitriles, (E)-3-aryloxy-acrylonitriles and 3-cyanobenzofurans through the sequential reactions of phenols with propiolonitriles
作者:Wei Zhou、Yicheng Zhang、Pinhua Li、Lei Wang
DOI:10.1039/c2ob25969a
日期:——
A Na2CO3-promoted addition of phenols to propiolonitriles generated (Z)-3-aryloxy-acrylonitriles in nearly quantitative yields with exclusively Z-isomers, and a DABCO-promoted addition reaction of phenols with propiolonitriles afforded mainly (E)-3-aryloxy-acrylonitriles with high yields. The obtained (E)-3-aryloxy-acrylonitriles underwent intramolecular cyclization to give 3-cyanobenzofurans in good yields through palladium-catalyzed direct C–H bond functionalization.
DMAP-promoted multicomponent reaction of cyanoacetylene, MBH carbonate and water: a facile access to functional quaternary carbon
作者:Ling-Guo Meng、Chun-Tao Li、Jin-Feng Zhang、Guo-Yuan Xiao、Lei Wang
DOI:10.1039/c3ra47105e
日期:——
An efficient method for the synthesis of highly functionalized products containing cyanide-substituted quaternary carbon centers via DMAP-promoted multicomponent reactions of cyanoacetylene, Morita–Baylis–Hillman (MBH) carbonate and water was developed. The reactions could be achieved under simple and mild conditions.
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.
chemoselective and metal/additive-free protocol for the synthesis of propargylic cyclic imine derivatives via (3 + 2)-cycloaddition of donor–acceptor cyclopropanes and alkynylnitriles in the presence of BF3·OEt2 has been established. The newly developed methodology provided access to a variety of propargylic cyclic imines in good to excellent yields. In addition, the synthesis of propargylic amines and the