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1.
The successive reduction of fully conjugated cyclic hydrocarbons leads to singly and multiply charged ions with unusual bonding. The charge distribution in these ions can be determined spectroscopically, and the information so obtained is then used in kinetically controlled trapping reactions for the regioselective introduction of electrophilic groups. When non-benzenoid substrates are used, syntheses become possible which can either not be carried out or can only be carried out with great difficulty in other ways. Examples of new preparative applications are cycloannelation and bridging reactions as well as polymerization reactions. The ion pair structure of the intermediate and the type of electrophile used are of paramount importance in controlling the mechanism of these reductive transformations.  相似文献   
2.
A modular approach to 5-acylated naphtho[2,1-b]benzofurans was developed where Sonogashira cross-coupling and intramolecular alkyne carbonyl metathesis were sequentially employed to build the aromatic benzene C ring of naphtho[2,1-b]benzofuran with an acyl group at the C5 position.  相似文献   
3.
Increasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon-carbon (C−C) bonds with isoelectronic boron-nitrogen (B−N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2N2 anthracene derivatives with two B−N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all-carbon analogue 2-phenylanthracene, BNBN anthracene exhibits significant variations in the C−C bond length and a larger highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light-emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics.  相似文献   
4.
Hatlike tribenzotriquinacenes 1 that bear six identical functional groups at the peripheral positions of the benzene nuclei were synthesized as starting materials for the construction of convex–concave organic networks and other three-dimensional molecular frameworks. X=NO2, NH2, Br, I, SnBu, Ph, CCPh.  相似文献   
5.
cis and trans-Aryl-2-azetidinone-tethered haloarenes can be stereoselectively prepared using the ketene-imine cyclization. These β-lactam-tethered haloarenes were used for the regiocontrolled preparation of β-lactam-biaryl hybrids including fused tetracyclic biaryl-2-azetidinones as well as C4-dearylated not fused biphenyl‐2-azetidinones via aryl-aryl radical cyclization and/or rearrangement. Alternatively, trans-dibenzocarbacephems could be stereoselectively prepared, both in racemic and enantiopure form, through the Staudinger reaction between phenanthridine and activated ketenes.  相似文献   
6.
4-Aryl-1,3-dihydroxy-2-naphthoates having the less accessible 1,2,3,4-tetrasubstituted naphthalene scaffold and that show photoluminescence emission from solid state as well as in solutions, were selectively synthesized from brominated lactol silyl ethers through the 1,2-aryl-migrative ring rearrangement reaction.  相似文献   
7.
The enantiomeric separations of highly hydrophobic furan derivatives and polycycles were performed and optimized using CD-modified micellar CE. The most effective chiral selector for the enantiomeric separation of these analytes was hydroxypropyl-gamma-CD. The effects of CD and SDS concentration and organic modifier were examined in order to optimize the separation conditions. The ratio of CD to surfactant concentration affected the enantiomeric separation significantly, with increases in the derivatized CD concentration generally enhancing resolution. Addition of an organic solvent modifier to the run buffer served to increase the analytes' solubility and enhance the separation efficiency. A highly acidic pH was necessary to effectively suppress the EOF when operating in the reverse polarity mode.  相似文献   
8.
9.
Amino-acid derived cross-conjugated trienes were used as a starting point for the synthesis of a discovery library of over 200 polycyclic 5-iminooxazolidin-2-ones, hydantoins, and acylureas. The main feature of this library synthesis is a triple branching strategy, which provides efficient access to five skeletally diverse scaffolds. In addition, four sets of building blocks were applied in both a front end and a back end diversification strategy. Multiple fused rings were obtained by cyclization of diamides with phosgene and stereoselective Diels-Alder reactions with maleimides. The 5-iminooxazolidin-2-one scaffold was rearranged into the isomeric hydantoin scaffold through a sequence of ring-opening and ring-closing reactions.  相似文献   
10.
An acid-catalyzed modular synthesis of substituted 5H-dibenz[c,e]azepines from a biaryl allylbenzamides prepared from the MBH adducts via a cascade dearoylation and intramolecular cyclization is described. The utility of the product for preparing 7,9-dihydro-4bH-dibenz[c,e]pyrrolo[1,2-a]azepine is also presented.  相似文献   
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