Asymmetric Ion-Pairing Catalysis Brak, Katrien; Jacobsen, Eric N.
Angewandte Chemie,
January 7, 2013, Volume:
52, Issue:
2
Journal Article
Peer reviewed
Open access
Charged intermediates and reagents are ubiquitous in organic transformations. The interaction of these ionic species with chiral neutral, anionic, or cationic small molecules has emerged as a ...powerful strategy for catalytic, enantioselective synthesis. This review describes developments in the burgeoning field of asymmetric ion‐pairing catalysis with an emphasis on the insights that have been gleaned into the structural and mechanistic features that contribute to high asymmetric induction.
Framing the field, this review provides an overview of four ion‐pairing strategies that have emerged for asymmetric catalysis of transformations proceeding through charged intermediates or reagents (see picture). Particular emphasis is placed on the mechanistic features that enable high asymmetric induction in these systems.
Martin Oestreich
European journal of organic chemistry,
June 22, 2018, Volume:
2018, Issue:
23
Journal Article
Peer reviewed
“The development of a catalytic cycle based on oxidative addition and reductive elimination at a main‐group element is an unsolved problem. Once discovered, it will become a hot topic!” Find out more ...about this author's research at https://doi.org/10.1002/ejoc.201800434.
“The development of a catalytic cycle based on oxidative addition and reductive elimination at a main‐group element is an unsolved problem. Once discovered, it will become a hot topic!” Find out more about this author's research at https://doi.org/10.1002/ejoc.201800434.
Building on our recent disclosure of catalysis at dinuclear PdI sites, we herein report the application of this concept to the realization of the first catalytic method to convert aryl iodides into ...the corresponding ArSeCF3 compounds. Highly efficient CSeCF3 coupling of a range of aryl iodides was achieved, enabled by an air-, moisture-, and thermally stable dinuclear PdI catalyst. The novel SeCF3-bridged dinuclear PdI complex 3 was isolated, studied for its catalytic competence and shown to be recoverable. Experimental and computational data are presented in support of dinuclear PdI catalysis.
The first asymmetric regio- and diastereodivergent gamma-allylation of cyclic alpha,beta-unsaturated aldehydes based on combined organocatalysis and transition-metal catalysis is disclosed. By ...combining an aminocatalyst with an iridium catalyst, both diastereomers of branched allylated products can be achieved in moderate to good yields and excellent regio- and stereoselectivities. Furthermore, by replacing the iridium catalyst with a palladium catalyst, the linear allylated products are formed in good yields and excellent regio- and enantioselectivities. The developed method thus provides selective access to all six isomers of the gamma-allylated product in a divergent fashion by choosing the appropriate combination of organocatalyst, transition-metal catalyst, and ligand.
The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective alpha-cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the ...coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology has also been applied to the total synthesis of the lignan natural product (-)-bursehernin.
The ability of a material to perform surface catalysis depends on the electronic structure features at the surface. Recent experiments on Fe.sub.2O.sub.3, one of the most studied water oxidation ...catalysts show that surface states may originate from adsorbed reaction intermediates that are cardinal for catalysis. Our recent theoretical DFT+U calculations confirm this hypothesis. In this paper, in order to account for more accurate electronic structure of the surface, we perform a one-shot GW calculation from a DFT+U wavefunction. We find that G.sub.0W.sub.0 overestimates the energy position of surface states, but provides good qualitative features of the surface's electronic structure.
As one environmentally benign technology for the removal of NO.sub.x, the selective catalytic reduction of NO.sub.x by hydrogen (H.sub.2-SCR) in the presence of oxygen has attracted more and more ...attention. Recent progress in the H.sub.2-SCR of NO.sub.x has been reviewed with the focus on H.sub.2-SCR catalysts and the reaction mechanisms. The effects of the reaction conditions (H.sub.2, O.sub.2, H.sub.2O, CO and SO.sub.2) on the performance of H.sub.2-SCR catalysts have been discussed. Finally, the future research direction for the H.sub.2-SCR of NO.sub.x has been proposed.
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