Visible‐light‐induced heterogeneous photocatalysis for decarboxylative alkynylation has been performed. The using of cheap, metal‐free and recyclable graphitic carbonnitride (g‐C3N4) as the photoredox catalyst in the process enables the facile transformation of a variety of carboxylic acids into structurally diverse alkyne‐containing molecular architectures under mild and environmentally‐benign conditions
可见光诱导的非均相光催化脱羧炔基反应。使用便宜,无金属且可回收的石墨氮化碳(g ‐ C 3 N 4)作为该过程中的光氧化还原催化剂,可以在温和和环境友好的条件下将多种羧酸轻松转化为结构多样的含炔分子结构。明显地,反应系统的非均质性质允许催化剂在多次运行中的回收和再利用而不损失反应性。光催化反应也可以以连续流动的方式进行并按比例放大至克级。此外,该策略在未活化烯烃的1,2氨基炔基化中的应用进一步凸显了该策略的制备能力。
Iron-Catalyzed Cross-Coupling of 1-Alkynylcyclopropyl Tosylates and Related Substrates
作者:Daniel J. Tindall、Helga Krause、Alois Fürstner
DOI:10.1002/adsc.201600357
日期:2016.7.28
1‐Alkynylcyclopropyl tosylates react with alkylmagnesium halides in the presence of catalytic ferric acetylacetonate [Fe(acac)3] under net propargylic substitution; allene formation, which is the prevalent reactivity mode of propargylic substrates otherwise, was noticed as a side reaction only when branched alkyl‐ or aryl‐Grignard reagents were used. These transformations represent the first successful iron‐catalyzed
The cyclopropyl effect on the regioselectivity of coupling reactions involving the lithiation of 1-cyclopropyl-2-arylacetylenes
作者:Shengming Ma、Qiwen He
DOI:10.1016/j.tet.2006.01.009
日期:2006.3
The cyclopropyl effect controlled the regioselectivity of the cross coupling reactions of propargylic/allenylic metallic species with electrophiles affording alkynic cycloproparies. It was proposed that the strain in cyclopropyl ring, which makes the formation of vinylidenecyclopropanes unfavorable, determined the regioselectivity. Control experiment of i-propyl, cyclobutyl, and cyclohexylphenylacetylenes were conducted to support the above speculation. (c) 2006 Elsevier Ltd. All rights reserved.