aryl ring
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2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jia-Lei Yan ◽  
Rakesh Maiti ◽  
Shi-Chao Ren ◽  
Weiyi Tian ◽  
Tingting Li ◽  
...  

AbstractAxially chiral styrenes bearing a chiral axis between a sterically non-congested acyclic alkene and an aryl ring are difficult to prepare due to low rotational barrier of the axis. Disclosed here is an N-heterocyclic carbene (NHC) catalytic asymmetric solution to this problem. Our reaction involves ynals, sulfinic acids, and phenols as the substrates with an NHC as the catalyst. Key steps involve selective 1,4-addition of sulfinic anion to acetylenic acylazolium intermediate and sequential E-selective protonation to set up the chiral axis. Our reaction affords axially chiral styrenes bearing a chiral axis as the product with up to > 99:1 e.r., > 20:1 E/Z selectivity, and excellent yields. The sulfone and carboxylic ester moieties in our styrene products are common moieties in bioactive molecules and asymmetric catalysis.


2021 ◽  
Vol 9 ◽  
Author(s):  
Qiuhua Zhu

Racemic C6-unsubstituted tetrahydropyrimidines (THPs) are the products of an efficient five-component reaction that we developed. THPs show strong AIE characteristics, that is, completely no fluorescence in different solvents but strong emission with fluorescence quantum yields (ΦF) up to 100% upon aggregation. However, the ΦF values of their pure enantiomers are lower than 46%. Unlike common AIE compounds with crowded aryl rotors on a π-bond or on an aryl ring, THPs have three completely non-crowded aryl rotors on a non-aromatic chiral central ring (tetrahydropyrimidine). In this mini review, we first discuss the AIE characteristics of THPs and the influences of molecular structures on their molecular packing modes and optical properties, and then present their applications and forecast the development of other racemic AIE compounds.


2021 ◽  
Author(s):  
Muhammad Siddique Ahmad ◽  
Zahid Shafiq

Abstract The present study reports a new organic CN reagent, 2-(piperidin-1-yl)acetonitrile which could cyanate commercially aryldiazonium tetrafluoroborate with Palladium as catalyst under mild reaction conditions. A large substrate scope for Pd-catalyzed cyanation of aromatic diazonium substrates was found, yielding cyanated products in medium to high amounts (50%‒88%). An attempt is also made to modify the method for preparation of etravirine and strategies for the transformations of 2-cyanoindole which are used as anti-AIDS, NMDA receptor antagonists and have high potential against mutant HIV strains. The mechanism of this Pd-catalyzed cyanation of aryldiazonium tetrafluoroborate involved CN ions construction was proved by paper indicator strategy. However, Pd/(Me3Si)2 system has been identified to cleave C − CN bond at low temperature and transferred the CN group to aryl ring of diazonium substrate in one pot.


2021 ◽  
Author(s):  
Jia-Lei Yan ◽  
Rakesh Maiti ◽  
Shi-Chao Ren ◽  
Weiyi Tian ◽  
Tingting Li ◽  
...  

Abstract Axially chiral styrenes bearing a chiral axis between a sterically non-congested acyclic alkene and an aryl ring are difficult to prepare due to low rotational barrier of the axis. Disclosed here is an N-heterocyclic carbene (NHC) catalytic asymmetric solution to this problem. Our reaction involves ynals, sulfinic acids, and phenols as the substrates with an NHC as the catalyst. Key steps involve selective 1,4-addition of sulfinic anion to acetylenic acylazolium intermediate and sequential E-selective protonation to set up the chiral axis. Our reaction affords axially chiral styrenes bearing a chiral axis as the product with up to >99:1 e.r., >20:1 E/Z selectivity, and excellent yields. The sulfone and carboxylic ester moieties in our styrene products are common moieties in bioactive molecules and asymmetric catalysis.


Synthesis ◽  
2021 ◽  
Author(s):  
Victor Martín-Heras ◽  
Constantin G. Daniliuc ◽  
Ryan Gilmour

The heptafluoroisopropyl group is emerging as a privileged chemotype in contemporary agrochemistry and features prominently in the current portfolio of leading insecticides. To reconcile the expansive potential of this module with the synthetic challenges associated with preparing crowded, fluorinated motifs, I(I)/I(III) catalysis has been leveraged. Predicated on in situ generation of p-TolIF2, this route enables the direct difluorination of α-trifluoromethyl-β-difluoro-styrenes in a single operation. This formal addition of fluorine across the alkene π-bond is efficient (up to 91%) and is compatible with a broad range of functional groups. The ArCF(CF3)2 moiety is conformationally pre-organized, with the C(sp3)-F bond co-planar to the framework of the aryl ring, thereby minimizing 1,3-allylic strain. Moreover, orthogonal multipolar C-F•••C=O interactions have been identified in a phathalimide derivative. It is envisaged that this programmed vicinal difluorination enabled by a hypervalent iodine species will find application in functional molecule design in a broader sense.


2021 ◽  
Vol 57 (77) ◽  
pp. 9882-9885
Author(s):  
Jiaqi Dong ◽  
Lutao Zhang ◽  
Dehui Tan ◽  
Jianfeng Wu ◽  
Nan Wang ◽  
...  
Keyword(s):  

A novel and air-stable organo(hydro)diborane featuring a five-membered aryl ring supported bridging B–C–B three-centre–two-electron (3c–2e) bond has been reported.


Author(s):  
Dhananjay S Nipate ◽  
Vikki N Shinde ◽  
R. Krishnan ◽  
Anil Kumar
Keyword(s):  

A condition-based switchable regioselective hydroalkylation of 2-arylindoles with maleimides has been developed. The reaction in the presence of Ru(II)-catalyst provided hydroalkylation at ortho-position of C2-aryl ring via C-H activation whereas...


2021 ◽  
Author(s):  
Antonio Aldair Castillo-García ◽  
González-Sebastián Lucero ◽  
Leticia Lomas-Romero ◽  
Simon Hernandez-Ortega ◽  
Ruben Alfredo Toscano ◽  
...  
Keyword(s):  

The synthesis of four novel non-symmetric Ni(II)-POCOP pincer complexes meta-functionalized with either benzothiazole or benzimidazole at the central aryl ring is described. All complexes were fully characterised in solution by...


2021 ◽  
Vol 23 (6) ◽  
pp. 3844-3855
Author(s):  
Kílian Jutglar Lozano ◽  
Raul Santiago ◽  
Jordi Ribas-Arino ◽  
Stefan T. Bromley

The electric field induced conformational response of a range of twistable dipolar aryl ring systems is studied using density functional theory based calculations. We assess which factors are most important for efficient molecular switching.


Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1149
Author(s):  
Denisa Dumitrescu ◽  
Sergiu Shova ◽  
Isabela C. Man ◽  
Mino R. Caira ◽  
Marcel Mirel Popa ◽  
...  

5-Iodo-1-arylpyrazoles are interesting templates for investigating the halogen bond propensity in small molecules other than the already well-known halogenated molecules such as tetrafluorodiiodobenzene. Herein, we present six compounds with different substitution on the aryl ring attached at position 1 of the pyrazoles and investigate them in the solid state in order to elucidate the halogen bonding significance to the crystallographic landscape of such molecules. The substituents on the aryl ring are generally combinations of halogen atoms (Br, Cl) and various alkyl groups. Observed halogen bonding types spanned by these six 5-iodopyrazoles included a wide variety, namely, C–I⋯O, C–I⋯π, C–I⋯Br, C–I⋯N and C–Br⋯O interactions. By single crystal X-ray diffraction analysis combined with the descriptive Hirshfeld analysis, we discuss the role and influence of the halogen bonds among the intermolecular interactions.


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