Ring-Walking of Zerovalent Nickel on Aryl Halides
Ring-Walking of Zerovalent Nickel on Aryl Halides
复制标题
DOI：
10.1021/acs.jctc.6b01143
复制
发表时间：
2017-04-01
影响因子：
5.5
通讯作者：
Allen, Wesley D.
中科院分区：
文献类型：
--
作者：
Bilbrey, Jenna A.;Bootsma, Andrea N.;Allen, Wesley D.
虽然环行走是过渡金属催化的交叉偶联反应中的关键步骤，但相关的亚稳中间体通常难以分离和表征。本文在B3 LYP-D3/TZ 2 P-LANL 2 TZ（f）-LANLO 8d水平上计算了零价镍与1-溴-2-甲苯、2-溴吡啶、2-溴-3-甲基噻吩和2-溴吡咯的环行走反应和氧化加成反应的理论结构和能量。该机制随底物环的大小和类型而定性地变化-催化剂沿着苯环和吡啶环的边缘编织，穿过噻吩环的内部切割，并沿着与吡咯环中的氮原子相对的键沿着成弧形。类似的计算上的环行走和氧化加成的零价钯与1-溴-2-甲基苯揭示了一个充满活力的配置文件类似的镍，但与弱得多的整体结合的芳烃。在所有情况下，色散校正被发现是非常重要的计算准确的金属衬底结合能。
While ring-walking is a critical step in transition metal catalyzed cross-coupling reactions, the associated metastable intermediates are often difficult to isolate and characterize. In this work, theoretical structures and energetics for ring walking and oxidative addition of zerovalent nickel with 1-bromo-2-methylbenzene, 2-bromopyridine, 2-bromo-3-methylthiophene, and 2-bromopyrrole were computed at the B3LYP-D3/TZ2P-LANL2TZ(f)-LANLO8d level. The mechanisms vary qualitatively with substrate ring size and type-the catalyst weaves along the edges of the benzene and pyridine rings, cuts through the interior of the thiophene ring, and arcs along the bond opposite the nitrogen atom in the pyrrole ring. Analogous computations on the ring-walking and oxidative addition of zerovalent palladium with 1-bromo-2-methylbenzene reveal an energetic profile similar to that of Ni but with much weaker overall binding to the arene. In all cases, dispersion corrections are found to be very important for computing accurate metal-substrate binding energies.