Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents
作者:Chi Wai Cheung、Peng Ren、Xile Hu
DOI:10.1021/ol501087m
日期:2014.5.2
cross-coupling of nonactivated secondary alkylbromides and iodides with alkynyl Grignardreagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.
<i>Z</i>-Selective Olefin Synthesis via Iron-Catalyzed Reductive Coupling of Alkyl Halides with Terminal Arylalkynes
作者:Chi Wai Cheung、Fedor E. Zhurkin、Xile Hu
DOI:10.1021/jacs.5b01784
日期:2015.4.22
Selective catalytic synthesis of Z-olefins has been challenging. Here we describe a method to produce 1,2-disubstituted olefins in high Z selectivity via reductive cross-coupling of alkylhalides with terminal arylalkynes. The method employs inexpensive and nontoxic catalyst (iron(II) bromide) and reductant (zinc). The substrate scope encompasses primary, secondary, and tertiaryalkylhalides, and
A Structure–Activity Study of Ni-Catalyzed Alkyl–Alkyl Kumada Coupling. Improved Catalysts for Coupling of Secondary Alkyl Halides
作者:Peng Ren、Oleg Vechorkin、Kim von Allmen、Rosario Scopelliti、Xile Hu
DOI:10.1021/ja200270k
日期:2011.5.11
of several well-defined Ni catalysts that are significantly more active and efficient than the pincercomplex [((Me)N(2)N)NiCl] for the coupling of secondary alkyl halides. The best two catalysts are [((H)NN)Ni(PPh(3))Cl] and [((H)NN)Ni(2,4-lutidine)Cl]. The improved activity and efficiency was attributed to the fact that phosphine and lutidine ligands in these complexes can dissociate from the Ni
对 Ni 催化的烷基-烷基熊田型交叉偶联反应进行了结构-活性研究。合成了一系列新的镍(II)配合物,包括具有三齿钳状双(氨基)酰胺配体((R)N(2)N)和具有双齿混合氨基-酰胺配体((R)NN)的配合物并对其进行了结构表征. 这些配合物的配位几何形状从方形平面、四面体到方形金字塔形。该配合物已被研究作为未活化的烷基卤化物,特别是仲烷基碘化物与烷基格氏试剂交叉偶联的预催化剂。与先前报道的 Ni 钳形复合物 [((Me)N(2)N)NiCl] 获得的结果进行了比较。预催化剂中的金属转移位点对于催化是必需的。预催化剂的配位几何形状和自旋状态影响很小或没有影响。这项工作导致发现了几种明确定义的 Ni 催化剂,这些催化剂比钳形复合物 [((Me)N(2)N)NiCl] 更活跃、更有效,用于偶联仲烷基卤化物。最好的两种催化剂是 [((H)NN)Ni(PPh(3))Cl] 和 [((H)NN)Ni(2
γ-Selective Allylation of (<i>E</i>)-Alkenylzinc Iodides Prepared by Reductive Coupling of Arylacetylenes with Alkyl Iodides
作者:Fedor E. Zhurkin、Xile Hu
DOI:10.1021/acs.joc.6b01306
日期:2016.7.1
allylic alkenylation using organozinc reagents are reported. (E)-Alkenylzinc iodides were prepared by Fe-catalyzed reductive coupling of terminal arylalkynes with alkyliodides. In the presence of a copper catalyst, these reagents reacted with allylic bromides derived from Morita–Baylis–Hillman alcohols to give 1,4-dienes in high yields. The reactions are highly γ-selective (generally γ/α > 49:1) and tolerate
Copper-Catalyzed Alkylation of Benzoxazoles with Secondary Alkyl Halides
作者:Peng Ren、Isuf Salihu、Rosario Scopelliti、Xile Hu
DOI:10.1021/ol300348w
日期:2012.4.6
Copper-catalyzed direct alkylation of benzoxazoles using nonactivated secondary alkylhalides has been developed. The best catalyst is a new copper(I) complex (1), and the reactions are promoted by bis[2-(N,N-dimethylamino)ethyl] ether.