Synthesis of Substituted [8]Cycloparaphenylenes by [2 + 2 + 2] Cycloaddition
摘要:
A new modular approach to the smallest substituted cycloparaphenylenes (CPPs) is presented. This versatile method permits access to substituted CPPs, choosing the substituent at a late stage of the synthesis. Variously substituted [8]CPPs have been synthesized, and their properties analyzed. The structural characteristics of substituted CPPs are close to those of unsubstituted CPPs. However, their optoelectronic behavior differs remarkably due to the larger torsion angle between the phenyl units.
已经开发出在催化量的偶氮二(异丁腈)作为自由基引发剂的存在下,二炔和硫代乙酸的单步分子内自由基级联反应以合成噻吩。该方法允许容易且有效地构建具有3,4-稠环取代和未取代的2,5-位的噻吩支架,用于进一步的官能化和聚合。使用该方法,合成了环戊[ c ]噻吩,3,4-乙撑二氧噻吩和含噻吩的螺环化合物的衍生物。
simply performed procedure for the [Rh(cod)Cl]2/cationic 2,2′-bipyridyl system-catalyzed [2+2+2] cycloaddition of α,ω-diynes with terminal and internal alkynes was achieved in waterunderair at 60 °C. The reaction proceeded smoothly with 1 equiv α,ω-diynes and 3 equiv alkynes in the presence of 20 mol % KOH for 1 h or 9 h, resulting in the formation of tri- and tetra-substituted benzene derivatives in
Insertion of (E)-(1,2-dihalovinyl)lithium and (2-haloethynyl)lithium into zirconacycles
作者:David Norton、Richard J. Whitby、Ed Griffen
DOI:10.1039/b403337j
日期:——
Insertion of (E)-(1,2-dihalovinyl)lithium into zirconacyclopentenes was followed by elimination of halide to afford an alkyne which inserts intramolecularly into the resulting carbon–zirconocenium bond to give a methylenecyclopentene, whereas insertion of (2-haloethynyl)lithium gives the same product via a zirconocene alkenylidene.
Cobalt Carbonyl-Catalyzed Tandem [2+2+1]/[4+2] Cycloaddition of Dienediyne to New Tetracycles
作者:Young Chung、Do Kim
DOI:10.1055/s-2005-871578
日期:——
A tandem reaction of dienediynes catalyzed by dicobalt octacarbonyl gives teracyclic compounds in a poor to high yield depending upon the substrate. The structural frame of the synthesized polycyclic compounds is disclosed for the first time in this study.
Rhodium-Catalyzed [2+2+2] Cycloaddition of Diynes with Carbodiimides and Carbon Dioxide under Ambient Conditions
作者:Masahiro Ishii、Fumiya Mori、Ken Tanaka
DOI:10.1002/chem.201304623
日期:2014.2.17
It has been established that a cationicrhodium(I)/H8‐binapcomplex is able to catalyze the [2+2+2] cycloaddition of diynes with carbodiimides and carbon dioxide under ambient conditions. Enantio‐ and/or regioselective variants of these reactions are also disclosed.
已经确定,在环境条件下,阳离子铑(I)/ H 8 Binap络合物能够催化二炔与碳二亚胺和二氧化碳的[2 + 2 + 2]环加成反应。还公开了这些反应的对映体和/或区域选择性变体。
Cobalt-mediated regio- and stereoselective assembly of dienamides by hydroaminative alkyne coupling of α,ω-diynes
作者:Vincent Gandon、Corinne Aubert、Max Malacria、K. Peter C. Vollhardt
DOI:10.1039/b716841a
日期:——
In the presence of CpCo(C(2)H(4))(2), alpha,omega-diynes undergo hydroaminative coupling with amides to furnish new dienamides with control of regio- and stereochemistry.