Palladium‐Catalyzed Cycloisomerizations of Diarylacetylenes: Synthesis, Structures, and Physical Properties of Highly Substituted Naphthalenes and 8,8 a‐Dihydrocyclopenta[<i>a</i>]indenes
Depending on the electronic properties of their substituents, the major products generated by palladium‐catalyzed cycloisomerizations of diarylalkynes are either highlysubstituted 8,8a‐dihydrocyclopenta[a]indenes 3 or naphthalenes 4. The structures of these compounds were verified by X‐ray crystallographic analysis. Many functional groups tolerated the reaction conditions evaluated in this study.
根据其取代基的电子特性,二芳基炔烃的钯催化环异构化反应生成的主要产物是高度取代的8,8a-二氢环戊[ a ]茚3或萘4。这些化合物的结构通过X射线晶体学分析进行了验证。许多官能团耐受本研究中评估的反应条件。同位素标记的实验表明,加水在形成这两类化合物中都起着至关重要的作用。系统研究了环加合物3及其类似物的光物理和电化学性质,并将其与基于密度泛函理论的计算预测进行了比较。二氢环戊[一个]茚3在为固体或液体形式显示强发光,而环戊二烯并[一个]茚11j中实际上是无荧光。直接连接到化合物3的主链上的官能团会显着影响物理性能。芳基取代基引起的空间效应引起不同的发光现象,包括聚集诱导和增强的发射。
Stereochemistry of hexakis (3-methoxyphenyl) benzene and hexakis(3-methylphenyl) benzene. An incremental chemical shift model formeta-substituted hexaphenylbenzenes
The 1H NMR spectrum of hexakis(3‐methoxyphenyl)benzene exhibits a methoxy absorption which looks exactly like a triplet. The spacing between the signals is, however, proportional to rather than independent of the field strength. The aryl H‐5 region of this compound and the methyl region of hexakis(3‐methylphenyl)benzene display similar field‐proportional, triplet‐like splittings. This property of meta‐substituted
Synthesis, Structure, and Photophysical Properties of Highly Substituted 8,8a-Dihydrocyclopenta[<i>a</i>]indenes
作者:Yao-Ting Wu、Ming-Yu Kuo、Yu-Ting Chang、Chien-Chueh Shin、Tsun-Cheng Wu、Chia-Cheng Tai、Tzu-Heng Cheng、Wei-Szu Liu
DOI:10.1002/anie.200802560
日期:2008.12.8
Nickel-Catalyzed Facile [2+2+2] Cyclotrimerization of Unactivated Internal Alkynes to Polysubstituted Benzenes
作者:Fei Xue、Ying Kai Loh、Xiaolu Song、Wei Jie Teo、J. Y. Darrence Chua、Jin Zhao、T. S. Andy Hor
DOI:10.1002/asia.201601469
日期:2017.1.3
A catalytic [2+2+2] cyclotrimerization of unactivated internal alkynes providing cyclotrimerization products in excellent yields with high regioselectivity is described. The transformation is accomplished by using a simple catalytic mixture comprising Ni(acac)2, an imidazolium salt and a Grignard reagent at room temperature or 60 °C for 20 min or 1 h.