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.
folded conformation and apparent through-space conjugation, were synthesized and studied as models to elucidate the AIE mechanism. The significant impacts of steric, conjugation and electronic effects on the AIE property are presented based on the results of crystallography analysis, optical spectra measurements and theoretical computation. Non-doped yellow organic light-emitting diodes were fabricated
The first example of catalytic enantioselective tautomerization of structurally labile but isolable enamines for accessing their chiral imine-tautomers is described. Kinetically stable enamine-based dibenzo[b,d]azepines were tautomerized by a simple chiral BINOL–phosphoric acid, providing a variety of seven-membered imine products bearing both central and axial stereogenic elements in good yields (up
<scp>Palladium‐Catalyzed</scp>
Oxidative Annulation of
<scp>
1‐Hydroxy‐
<i>o</i>
‐Carborane
</scp>
with Internal Alkynes: Facile Synthesis of
<scp>Carborane‐Fused</scp>
Oxaboroles
<sup>†</sup>
作者:Ruofei Cheng、Zaozao Qiu、Zuowei Xie
DOI:10.1002/cjoc.202000307
日期:2020.12
catalyzed oxidative annulation of 1‐hydroxy‐o‐carborane with internal alkynes via regioselective B(3)—H bond activation has been developed for facile synthesis of a series of C,B‐substituted carborane‐fused oxaboroles. These molecules can undergo intramolecularoxidative dehydrogenative coupling to afford carborane‐fused large π systems for potential applications in organic materials. The reaction mechanism
Palladium-Catalyzed Dimerization of Bis(2-biphenylyl)acetylene toward Sterically Hindered Acephenanthrylene
作者:Maximilian Ackermann、Jan Freudenberg、Daniel Jänsch、Frank Rominger、Uwe H. F. Bunz、Klaus Müllen
DOI:10.1021/acs.orglett.8b01334
日期:2018.7.6
reaction of 2,2′′-(1,2-ethynediyl)bis-1,1′-biphenyl under homogeneous (heterogeneous) catalysis with Pd/C/TMS-Cl results in a dimerization and the additional formation of five- and six-membered rings. The steric demand of the acetylene prevents a [2 + 2 + 2] cycloaddition, but paves the way toward an alternative reaction. By the formation of an unexpected planar acephenanthrylene, the system avoids steric
2,2''-(1,2-乙炔二基)双-1,1'-联苯在Pd / C / TMS-Cl的均相(非均相)催化下的反应导致二聚化并进一步形成五-和-六元环。乙炔的空间需求阻止了[2 + 2 + 2]环加成反应,但为替代反应铺平了道路。通过形成意外的平面对苯乙炔,该系统避免了空间污染。探索了合成范围和要求,并提出了反应机理。
Iridium-catalyzed regioselective B(3,6)-dialkenylation or B(4)-alkenylation of <i>o</i>-carboranes <i>via</i> B–H activation and 1,2-carbon migration of alkynes
An efficient and highly selective Ir-catalyzed cage boron alkenylation of o-carboranes with diarylacetylenes coupled with 1,2-aryl migration has been developed, leading to B–H geminal addition products via vinylidene rearrangement.