Palladium-catalyzed double cross-coupling reaction of 1,2-bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls: annulative approach to functionalized polycyclic aromatic hydrocarbons
This study demonstrates that the doublecross-coupling reaction of 1,2-bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls proceeds smoothly with the aid of a catalytic amount of Pd(PPh3)4 in the presence of excess base to give a variety of polycyclic aromatic hydrocarbons, such as phenanthrenes, [5]helicene, dithienobenzenes, triphenylenes, dibenzo[g,p]chrysenes, and triphenyleno[1,2-b:4
这项研究表明,在催化量的Pd(PPh 3)4存在下,1,2-双(频哪醇硼基)烯烃和-芳烃与2,2'-二溴联芳基的双交叉偶联反应可以顺利进行。过量的碱可得到各种多环芳烃,例如菲,[5]螺旋烯,二硫代苯,三苯撑,二苯并[ g,p ],和三苯并[1,2- b:4,3- b ']二噻吩好到高产。值得注意的是,使用2,2'-二溴八氟联苯作为亲电试剂的环化反应提供了否则难以合成的八氟菲和半氟化二苯并[ g,p] chrysenes高产。
Stable Borepinium and Borafluorenium Heterocycles: A Reversible Thermochromic “Switch” Based on Boron–Oxygen Interactions
作者:Wenlong Yang、Kelsie E. Krantz、Lucas A. Freeman、Diane A. Dickie、Andrew Molino、Aishvaryadeep Kaur、David J. D. Wilson、Robert J. Gilliard
DOI:10.1002/chem.201903348
日期:2019.9.25
reversible colorimetric "turn off/turn on" properties in solution. Notably, this is the first report of thermochromism in these cationic species. This property, which is mediated by an intermolecular boron-oxygenbond equilibrium, was examined in detail by X-ray crystallography, variable temperature-UV/Vis absorption spectroscopy (VT-UV/Vis), and density functional theory (DFT).