Asymmetric calixarene derivatives as potential hosts in chiral recognition processes

2015 ◽  
Vol 87 (4) ◽  
pp. 415-439 ◽  
Author(s):  
Catalin V. Maftei ◽  
Elena Fodor ◽  
Peter G. Jones ◽  
M. Heiko Franz ◽  
Corneliu M. Davidescu ◽  
...  
Keyword(s):  
Chiral Recognition ◽  
Hydrogen Transfer ◽  
Amide Bond ◽  
Transfer Reactions ◽  
Ester Bond ◽  
X Ray ◽  
Tert Butyl ◽  
Asymmetric Catalytic ◽  
Catalytic Hydrogen ◽  
Derivatives Of

AbstractNew chiral derivatives of 15,35,55,75-tetra-tert-butyl-1,3,5,7(1,3)-tetrabenzenacyclooctaphane-12,32,52,72-tetraol [(1); tert-butyl-calix[4]-arene] were synthesized by coupling modified chiral quinuclidines derived from the natural-product-based alkaloids quincorine and quincoridine with the calix[4]arene 1 via either an ester bond or an amide bond. X-ray analyses of two products were performed. Applications of the products in asymmetric catalytic hydrogen transfer reactions are described. A protocol is presented to multi-substitute calix[4]arene at the methylene bridges, resulting in, e.g., 2,6-carboxyl-all-tert-butyl all-methoxy-calix[4]arene.

Preparation of Carboranyl and Dodecaborate Derivatives of Coumarin

2007 ◽  
Vol 72 (12) ◽  
pp. 1740-1754 ◽  
Author(s):  
Eugen Justus ◽  
Dana T. Izteleuova ◽  
Alexander V. Kasantsev ◽  
Mendel M. Axartov ◽  
Enno Lork ◽  
...  
Keyword(s):  
Structure Analysis ◽  
The Other ◽  
Magnesium Salt ◽  
Ester Bond ◽  
Coumarin Derivatives ◽  
X Ray ◽  
Derivatives Of ◽  
Coumarin Ring

A series of derivatives of coumarin (2H-chromen-2-one) and 6,7-benzocoumarin (3H-benzo-[f]chromen-3-one) carrying the o-carborane, m-carborane, and dodecaborate clusters, has been obtained. X-ray structure analysis has been carried out for three of the products. The addition of o-carborane occurs in the 4-position of the coumarin ring, in a stereoselective way, independent of whether the cluster was reacted as the lithium or magnesium salt. m-Carborane gives two products, one being the result of 1,2-addition to an exocyclic ester bond and 1,4-addition to the coumarin system, the other resulting from 1,4-addition. The negatively charged dodecaborate derivatives obtained, link the cluster via oxygen or sulfur and an appropriate linker to a 7-hydroxy-substituted coumarin. For the coumarin derivatives, an o-carboranecarbonyl derivative could also be obtained.

scholarly journals Synthesis and Structure of (Nitronyl Nitroxide-2-ido)(tert-butyldiphenylphosphine)gold(I) and -(Di(tert-butyl)phenylphosphine)gold(I) Derivatives; Their Comparative Study in the Cross-Coupling Reaction

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 770
Author(s):  
Igor Zayakin ◽  
Irina Bagryanskaya ◽  
Dmitri Stass ◽  
Maxim Kazantsev ◽  
Evgeny Tretyakov
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Oxidation Potential ◽  
Nitronyl Nitroxide ◽  
X Ray ◽  
Tert Butyl ◽  
Cross Coupling Reaction ◽  
Vis Spectroscopy ◽  
The Cross ◽  
Derivatives Of

We synthesized two new organogold derivatives of a nitronyl nitroxide (NN) with phosphine ligands, namely NN-Au-PtBuPh2 and NN-Au-PtBu2Ph. They were characterized by X-ray diffraction analysis, cyclic voltammetry, and ESR, IR, and UV/Vis spectroscopy. The X-ray structural analysis revealed a tendency of the NN moiety to form a large number of short intermolecular contacts. This phenomenon is related to the anionic nature of the paramagnetic group NN, as evidenced by a significantly lower oxidation potential in comparison with purely organic derivatives of NN radicals. The cross-coupling reaction of NN-Au-PPh3, NN-Au-PtBuPh2, or NN-Au-PtBu2Ph with an activated bromoarene, namely, p-BrC6H4NO2, was investigated. It was shown that regardless of the presence of the bulky tert-butyl substituent, all gold derivatives have similar activities in the cross-coupling reaction and give a cross-coupling product, NN-C6H4NO2, with comparable yields.

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