Karbeny N-heterocykliczne : synteza i zastosowanie
Journal Title: Wiadomości Chemiczne - Year 2015, Vol 69, Issue 3
Abstract
N-Heterocyclic carbenes (NHCs) are powerful tools in organic chemistry, with numerous applications in academic and industrial laboratories. They are usually defined as singlet carbenes, in which the divalent carbonic centre is connected directly to at least one nitrogen atom in the heterocycle [1]. They have played an important role in organic chemistry ever since the first evidence of their existence. The isolation of stable, free 1,3‑diadamantylimidazol-2-ylidene (IAd, Fig. 1) by Arduengo et al. in 1991 was a milestone in the chemistry of carbenes [2]. From the beginnings as academic curiosities, N‑heterocyclic carbenes today are very useful compounds in a variety of organic transformations (Fig. 13). NHCs are neutral σ-donors, which form very strong bonds with the majority of transition metals (stronger than phosphines). These compounds are easy-to-make ligands with great potential in homogeneous catalysis (mainly ruthenium and palladium complexes) for large number of reactions, including the coupling reactions (Heck, Negishi, Stille, Suzuki or Sonogashira reactions) and olefin metathesis [3]. Moreover, they are very useful as organocatalysts used in the benzoin condensation, the Stetter reaction and ring-opening polymerization (ROP) or transesterification [4]. In this review, we aim to give an overview of the properties and applications of NHCs, which we expect will be a useful introduction for chemists interested in studying and applying these important compounds. The first part of this review is devoted to the main synthetic routes to NHCs, their properties and reactivity. In the second part we describe the metal complexes with NHCs as homogeneous catalysts and their applications in various types of reactions. At the end of this part of the paper the use of NHCs as organocatalysts is presented.
Authors and Affiliations
Marta Malinowska, Agnieszka Hryniewicka
Enancjoselektywna enzymatyczna desymetryzacja katalizowana oksydoreduktazami. Reakcje utleniania. Część 2
In continuation of our work, we herein describe next enzyme classes applied for oxidation reaction. Dioxygenases, oxidases, and peroxidases are successfully used in the synthesis of desymmetrization products with high yi...
Fotofizyczne podstawy znakowania chemiluminescencyjnego–nowoczesnego narzędzia diagnostyki medycznej
Increasing exposition of people on the factors which negatively affect health lead to the escalation in the incidence of many diseases. In the same time, this phenomenon causes the intensification in research focusing on...
Atroposelektywna synteza naturalnych chiralnych osiowo związków biarylowych. Część 2
A direct aryl-aryl coupling reaction is the most common method for the synthesis of axially chiral biaryls. Atroposelective coupling can be accomplished by three main strategies (Scheme 1) [1, 11]: a) intramolecular coup...
Materiały kompozytowe MOF-grafen
The effective capture of harmful gases and clean energy sources are of great importance for protection of the environment. In this regard, it is possible to take advantage of the MOF-graphene composites to develop new te...
Badanie elektrochemicznej absorpcji wodoru w palladzie i jego stopach przy użyciu elektrod o ograniczonej objętości
The review summarizes the results of the electrochemical studies on hydrogen absorption in Pd and Pd alloys prepared in the form of thin deposits on a hydrogen -neutral matrix. This kind of electrodes, called Limited Vol...