Direct Manipulation of Metal Imido Geometry: Key Principles to Enhance C–H Amination Efficacy
作者:Yunjung Baek、Elisabeth T. Hennessy、Theodore A. Betley
DOI:10.1021/jacs.9b09015
日期:2019.10.23
Multinuclear NMRspectroscopy and solid-state magnetic susceptibility measurements were used to determine that (TrL)Co(NAd) exhibits a low-spin CoIII electronic configuration. Exposure of 1-10 mol% of (TrL)Co to linear alkyl azides (RN3) resulted in catalytic formation of substituted N-heterocycles via intramolecular C-H amination of a range of C-H bonds, including primary C-H bonds. The mechanism of the
我们报告了由具有空间阻碍的三苯甲基取代基(TrL)(TrL = 5-mesityl-1,9-(trityl)dipyrrin 的二吡咯-亚甲基配体支持的可分离 CoIII 亚胺复合物(TrL)Co(NR)介导的催化 CH 胺化)。(TrL)Li 与 CoCl2 在 THF 中的金属化提供了一种独特的三角锥几何形状的高自旋 (S = 3/2) 三配位配合物 (TrL) CoCl,显示了钴和其中之一之间的 η1-芳烃相互作用。来自三苯甲基侧翼基团的邻碳。(TrL)CoCl 与钾石墨的化学还原产生高自旋 (S = 1) CoI 合成子 (TrL)Co,其通过与三苯甲基部分苯基取代基之一的分子内 η6-芳烃相互作用稳定。用化学计量的 1-叠氮金刚烷 (AdN3) 处理 (TrL)Co 提供了三配位 CoIII 酰亚胺 (TrL)Co(NAd),如单晶 X 射线衍射所证实。有趣的是,(TrL)Co(NAd)
Tetrahydronaphthalene Derivatives by Amberlyst® 15-Promoted Friedel-Crafts Cyclizations
作者:Richard A. Bunce、Andrew N. Cox
DOI:10.1080/00304940903523553
日期:2010.2.2
Friedel–Crafts cyclization of tertiary alcohols using bismuth(III) triflate
作者:Baskar Nammalwar、Richard A. Bunce
DOI:10.1016/j.tetlet.2013.06.026
日期:2013.8
Bismuth(III) triflate [Bi(OTf)(3)] has been developed as an efficient and mild catalyst for intramolecular Friedel-Crafts cyclizations of tertiary alcohols to prepare disubstituted tetrahydronapthalenes, chromans, thiochromans, tetrahydroquinolines, and tetrahydroiso-quinolines. The method represents a unified strategy to synthesize a variety of ring systems from tertiary alcohols using a common Lewis acid. (C) 2013 Elsevier Ltd. All rights reserved.
Catalytic C–H Amination Mediated by Dipyrrin Cobalt Imidos
作者:Yunjung Baek、Theodore A. Betley
DOI:10.1021/jacs.9b01262
日期:2019.5.15
requiring product sequestration. The imido (ArL)Co(NAd) exists in equilibrium in the presence of pyridine with a four-coordinate cobaltimido (ArL)Co(NAd)(py) ( Ka = 8.04 M-1), as determined by 1H NMR titration experiments. Kinetic studies revealed that pyridine binding slows down the formation of the tetrazido complex by blocking azide coordination to the CoIII imido. Further, (ArL)Co(NR)(py) displays