Bimacrocyclic concave N-heterocyclic carbenes (NHCs): Synthesis, structure and application in catalyses
نویسندگان
چکیده
منابع مشابه
Anionic N-heterocyclic carbenes (NHCs): a versatile route to saturated NHCs bearing pendant weakly coordinating anions.
A versatile methodology is reported for the synthesis of anionic NHCs featuring a 5-, 6-, or 7-membered saturated heterocyclic core. Lewis acid promoted exocyclic ring closure generates systems in which the pendant borate functionality is incorporated via a CH2 linker, allowing for electronic and steric isolation of the anionic component. Hence, a library of NHCs can be accessed which incorpora...
متن کاملSynthesis of phosphorus esters by transesterification mediated by N-heterocyclic carbenes (NHCs).
The versatile nucleophilic organic catalysts N-heterocyclic carbenes (NHCs) have been shown to effectively mediate the transesterification of phosphorus esters under mild conditions; user-friendly imidazolium salts can also be employed as pre-catalysts.
متن کاملN-Heterocyclic carbenes
The N-heterocyclic carbenes (NHC) now hold a preferredligand status in organic and organometallic chemistry. Their role in catalysis continues to grow. When the editorial staff at the Beilstein Journal of Organic Chemistry contacted me to act as a guest editor for the thematic series “N-Heterocyclic carbenes”, I was more than happy to accept what appeared to me to be a simple and exciting endea...
متن کاملSydnone anions and abnormal N-heterocyclic carbenes of O-ethylsydnones. Characterizations, calculations and catalyses.
Deprotonated sydnones, which can be represented as anionic N-heterocyclic carbenes, were prepared as Li adducts and compared with deprotonated O-ethylsydnones (5-ethoxy-1,2,3-oxadiazol-4-ylidenes) which belong to the class of abnormal NHCs. The Pd complexes of the sydnone anions (X-ray analysis) as well as of the O-ethylsydnone carbenes proved to be efficient catalysts in aryl couplings of thio...
متن کاملThe study of the electronic structure of some N-heterocyclic carbenes (NHCs) by variable energy photoelectron spectroscopy.
The photoionization of three N-heterocyclic carbenes (NHCs) has been studied in the valence and core regions using synchrotron radiation. We observed different variations in the relative band intensities with photon energy for the NHCs in the valence ionization region. This is due to the intra-ring interactions between the C=C bond, nitrogen and carbene lone pairs in the heterocyclic ring of NH...
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ژورنال
عنوان ژورنال: Supramolecular Chemistry
سال: 2009
ISSN: 1061-0278,1029-0478
DOI: 10.1080/10610270802468413