Compared with heteroarenes, homogeneous asymmetric hydrogenation of all-carbon aromatic rings is a longstanding challenge in organic synthesis due to the strong aromaticity and difficult enantioselective control. Herein, we report the rhodium/diphosphine-catalyzed asymmetric hydrogenation of all-carbon aromatic rings, affording a series of axially chiral cyclic compounds with high enantioselectivity through desymmetrization or kinetic resolution. In addition, the central-chiral cyclic compounds were also obtained by asymmetric hydrogenation of phenanthrenes bearing a directing group. The key to success is the introduction of chiral diphosphine ligands with steric hindrance and strong electron-donating properties. The axially chiral monophosphine ligands could be obtained by simple conversion of the hydrogenation products bearing the phosphine atom.
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http://dx.doi.org/10.1002/anie.202205623 | DOI Listing |
J Am Chem Soc
January 2025
Department of Materials Science, Fudan University, Shanghai 200433, China.
Borohydrides, known for ultrahigh hydrogen density, are promising hydrogen storage materials but typically require high operating temperatures due to their strong thermodynamic stability. Here we introduce a novel light-induced destabilization mechanism for hydrogen storage reaction of borohydrides under ambient conditions photogenerated vacancies in LiH. These vacancies thermodynamically destabilize B-H bonds through the spontaneous "strong adsorption" of BH groups, which trigger an asymmetric redistribution of electrons, enabling hydrogen release at near room temperature, approximately 300 °C lower than the corresponding thermal process.
View Article and Find Full Text PDFOrg Lett
January 2025
Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
This work describes a chiral bifunctional squaramide/DBU sequential catalytic strategy for the enantioselective synthesis of nonfused chiral eight-membered O-heterocycles through the asymmetric addition of ynones to β,γ-unsaturated α-ketoesters followed by the regio- and diastereoselective cyclization of the adduct intermediates. Mechanistic experiments revealed that an isomerization process should be involved in the ring formation step, and the origin of the high regioselectivity and diastereoselectivity has also been elucidated by the DFT calculations.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China.
The azahelicenes are structurally fascinating and practically useful chiral scaffolds, but their synthesis, especially in a catalytically asymmetric manner, is rather challenging. Herein, we report a CPA-catalyzed transfer hydrogenation process, which enables a rapid kinetic resolution of aza[6]helicenes. The established strategy provides facile access to enantioenriched aza[6]helicenes and tetrahydro[6]helicenes from easily available starting materials.
View Article and Find Full Text PDFChemistry
January 2025
Manchester Interdisciplinary Biocentre: The University of Manchester Manchester Institute of Biotechnology, Biotechnology and chemical engineering, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Hypohalites are commonly generated in biological systems, mostly with functions related to defense and immune system response. These hypohalites can bind to metal centers and are known for their strong oxidizing properties that play crucial roles in various biological processes. Herein, we report the synthesis, characterization and reactivity of novel biomimetic Ru(III)-hypochlorite complexes and focus the work on the electronic effects associated with the incorporation of methyl groups in a pentadentate ligand framework in an asymmetric fashion.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, Kaiser-Wilhelm-Platz 1, 45470, Mülheim/Ruhr, GERMANY.
Ynamides, when reacted with H2 or HBpin in the presence of [Cp*RuCl]4, convert into chiral-at-metal Fischer carbenes by regioselective gem-hydrogenation or gem-hydroboration of the polarized triple bond, respectively. gem-Hydroboration concomitantly affords a carbogenic borylated stereocenter adjacent to the ruthenium carbene unit, the configuration of which can be controlled using an Evans auxiliary. These are the first examples of asymmetric gem-addition reactions to alkynes known in the literature; representative pianostool ruthenium carbene complexes formed by this unconventional route were characterized by crystallographic and spectroscopic means.
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