苯并[ b ]噻吩杂环是许多重要的小分子药物和候选药物以及有机半导体材料的重要组成部分。已经开发了许多通过炔烃的环化反应来构建苯并[ b ]噻吩核的方法。尽管公开的催化反应很少,但是大多数方法依赖于炔烃的化学计量活化。在这里我们报告了一种由金催化的由2-炔基硫代苯甲醚合成2-取代的苯并[ b ]噻吩的有效方法(I)– IPr氢氧化物,适用于具有多种电子和空间特性的多种底物。另外,我们通过实验证明了酸添加剂及其共轭碱对催化剂周转至关重要。
Cobalt-Catalyzed Negishi Cross-Coupling Reactions of (Hetero)Arylzinc Reagents with Primary and Secondary Alkyl Bromides and Iodides
作者:Jeffrey M. Hammann、Diana Haas、Paul Knochel
DOI:10.1002/anie.201411960
日期:2015.4.7
di(hetero)arylzinc reagents with primary and secondaryalkyliodides or bromides using THF‐soluble CoCl2⋅2 LiCl and TMEDA as a ligand, which leads to the corresponding alkylated products in up to 88 % yield. A range of functional groups (e.g. COOR, CN, CF3, F) are tolerated in these substitution reactions. Remarkably, we do not observe rearrangement of secondaryalkyliodides to unbranched products. Additionally
A potassium hydroxide/dimethyl sulfoxide (KOH/DMSO) superbase‐promoted method for the synthesis of 2‐substituted benzothiophenes has been developed via photoinduced intermolecular annulation of 2‐halothioanisoles with terminal alkynes at ambient temperature. The present protocol uses commercially available 2‐halothioanisoles as substrates and visible light as energy force, which offers a wide range
Alkylations of Arylboronic Acids including Difluoroethylation/Trifluoroethylation<i>via</i>Nickel-Catalyzed Suzuki Cross-Coupling Reaction
作者:Xiaofei Zhang、Chunhao Yang
DOI:10.1002/adsc.201500346
日期:2015.8.24
An efficient alkylation method of functionalized alkyl halides under mild nickel‐catalyzed C(sp3)C(sp2) Suzuki cross‐coupling conditions is described. The features of this approach are excellent functional group compatibility, low cost nickel catalyst, and the use of a mild base. This is also the first successful example of the nickel‐catalyzed direct 2,2‐difluoroethylation or 2,2,2‐trifluoroethylation
Iron-Catalyzed Heterocycle and Arene Deprotonative Alkylation
作者:Ly Dieu Tran、Olafs Daugulis
DOI:10.1021/ol101684u
日期:2010.10.1
A method for iron-catalyzed deprotonative alkylation of arene C−H bonds by alkyl iodides and bromides has been developed. In the presence of an amide base, both primary and secondary alkyl halides can be coupled with furans, thiophenes, pyridine derivatives, and some electron-withdrawing-group containing arenes.