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
Avoiding Olefin Isomerization During Decyanation of Alkylcyano α,ω-Dienes: A Deuterium Labeling and Structural Study of Mechanism
作者:Giovanni Rojas、Kenneth B. Wagener
DOI:10.1021/jo800640j
日期:2008.7.1
pathway involving decyanation chemistry for the synthesis of pure alkyl α,ω-dienes in quantitative yields is presented. Prior methodologies for the preparation of such compounds required 6−9 steps, sometimes leading to product mixtures resulting from olefin isomerization chemistry. This isomerization chemistry has been eliminated. Deuteration labeling and structural mechanistic investigations were completed
作者:Marie E. Krafft、William J. Crooks、Branka Zorc、Stephen E. Milczanowski
DOI:10.1021/jo00249a007
日期:1988.7
From Dimethylamine to Pyrrolidine: The Development of an Improved Nickel Pincer Complex for Cross-Coupling of Nonactivated Secondary Alkyl Halides
作者:Pablo M. Perez Garcia、Thomas Di Franco、Alexandre Epenoy、Rosario Scopelliti、Xile Hu
DOI:10.1021/acscatal.5b02324
日期:2016.1.4
Replacement of a dimethyl amino group of the amidobis(amine) nickel(II) pincer complex (1), [((N2N)-N-Me)-Ni-Cl], by a pyrrolidino group resulted in a new nickel(II) pincer complex (2), [((PNNN)-N-yr-N-Me)Ni-Cl]. Complex 2 is an efficient catalyst for Kumada and Suzuki-Miyaura cross-coupling of nonactivated secondary alkyl halides, while complex 1 is largely inactive. The significant activity difference is tentatively attributed to a minimal structural difference, which leads to a more hemilabile ligand.
Auclair,F. et al., Bulletin de la Societe Chimique de France, 1976, p. 142 - 144