Journal ArticleDOI
Cyclic (alkyl)(amino)carbenes (CAACs): stable carbenes on the rise.
TLDR
This Account discusses another class of stable cyclic carbenes, namely, cyclic (alkyl)(amino)carbenes (CAACs), and shows that the peculiar electronic and steric properties of CAACs allow for the stabilization of unusual diamagnetic and paramagnetic main group element species.Abstract:
ConspectusCarbenes are compounds that feature a divalent carbon atom with only six electrons in its valence shell. In the singlet state, they possess a lone pair of electrons and a vacant orbital and therefore exhibit Lewis acidic and Lewis basic properties, which explains their very high reactivity. Following the preparation by our group in 1988 of the first representative, a variety of stable carbenes are now available, the most popular being the cyclic diaminocarbenes.In this Account, we discuss another class of stable cyclic carbenes, namely, cyclic (alkyl)(amino)carbenes (CAACs), in which one of the electronegative and π-donor amino substituents of diaminocarbenes is replaced by a σ-donating but not π-donating alkyl group. As a consequence, CAACs are more nucleophilic (σ-donating) but also more electrophilic (π-accepting) than diaminocarbenes. Additionally, the presence of a quaternary carbon in the position α to the carbene center provides steric environments that differentiate CAACs dramatically fr...read more
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Journal ArticleDOI
Cyclic (Alkyl)(amino)carbenes (CAACs): Recent Developments
TL;DR: The most important results published up to the end of 2013 are briefly summarized, while the majority of this Review focuses on findings reported within the last three years.
Journal ArticleDOI
What is NBO analysis and how is it useful
TL;DR: Natural bond orbital (NBO) analysis is one of many available options for translating computational solutions of Schrodinger's wave equation into the familiar language of chemical bonding concepts as discussed by the authors.
Journal ArticleDOI
NHCs in Main Group Chemistry.
Vitaly Nesterov,Dominik Reiter,Prasenjit Bag,Philipp Frisch,Richard Holzner,Amelie Porzelt,Shigeyoshi Inoue +6 more
TL;DR: A general overview of the chemistry of low-coordinate main group element compounds, basic synthetic approaches, key features of NHC-main group element adducts, and might be useful for the broad research community are given.
Journal ArticleDOI
N-Heterocyclic Carbene Complexes in C–H Activation Reactions
TL;DR: Through discussing the role of NHC ligands in promoting challenging C-H activation methods, the reader is provided with an overview of this important area and its crucial role in forging carbon-carbon and carbon-heteroatom bonds by directly engaging ubiquitous C- H bonds.
Journal ArticleDOI
Mesoionic and Related Less Heteroatom-Stabilized N-Heterocyclic Carbene Complexes: Synthesis, Catalysis, and Other Applications.
TL;DR: Mesoionic carbenes as discussed by the authors are a subclass of the family of N-heterocyclic Carbenes that generally feature less heteroatom stabilization of the carbenic carbon and hence impart specific donor properties and
References
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A stable crystalline carbene
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Organocatalytic umpolung: N-heterocyclic carbenes and beyond
TL;DR: This tutorial review aims at offering a didactic overview of organocatalytic umpolung and should serve as an inspiration for further progress in this field.