Teresa Corona, Lídia Ribas, Mireia Rovira, Dr. Erik R. Farquhar, Dr. Xavi Ribas , Prof. Dr. Kallol Ray , Dr. Anna Company First published: 10 October 2016 Full publication history DOI: 10.1002/anie.201607238 View/save citation http://onlinelibrary.wiley.com/doi/10.1002/anie.201607238/full Abstract High-valent terminal copper–nitrene species have been postulated as key intermediates in copper-catalyzed aziridination and amination reactions. The high reactivity of these intermediates has prevented their characterization for decades, thereby making the mechanisms ambiguous. Very recently, the Lewis acid adduct of a copper–nitrene intermediate was trapped at −90 °C and shown to be active in various oxidation reactions. Herein, we describe for the first time the synthesis and spectroscopic characterization of a terminal copper(II)–nitrene radical specie...
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Highly EnantioselectiveIron-Catalyzed cis-Dihydroxylation ofAlkenes with Hydrogen Peroxide Oxidant via an FeIII-OOH ReactiveIntermediate
Chao Zang + , Yungen Liu + , Zhen-Jiang Xu, Chun-Wai Tse, Xiangguo Guan, Jinhu Wei, Jie- Sheng Huang, and Chi-Ming Che* [*] Dr. C. Zang, [+] Dr. Z.-J. Xu, Prof. Dr. C.-M. Che Shanghai–Hong Kong Joint Laboratory in Chemical Synthesis Shanghai Institute of Organic Chemistry 354 Feng Lin Road, Shanghai (China) E-mail: cmche@hku.hk Dr. Y. Liu, [+] C.-W. Tse, Dr. X. Guan, J. Wei, Dr. J.-S. Huang, Prof. Dr. C.-M. Che Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (China) [ + ] These authors contributed equally to this work. http://onlinelibrary.wiley.com/doi/10.1002/anie.201603410/abstract Abstract The development of environmentally benign cata- lysts for highly enantioselective asymmetric cis-dihydroxyla- tion (AD) of alkenes with broad substrate scope remains a challenge. By employing [Fe II (L)(OTf) 2 ] (L = N,N ’ - dimethyl-N,N ’ -bis(2-methyl-8-quinolyl)-cyclohexane-1...
A Ruthenium(III)–Oxyl Complex Bearing Strong Radical Character Yoshihiro Shimoyama, Tomoya Ishizuka, Hiroaki Kotani, Yoshihito Shiota, Kazunari Yoshizawa, Kaoru Mieda, Takashi Ogura, Toshihiro Okajima, Shunsuke Nozawa, and Takahiko Kojima* Abstract Proton-coupled electron-transfer oxidation of a RuII OH2 complex, having an N-heterocyclic carbene ligand, gives a RuIII OC species, which has an electronically equivalent structure of the RuIV=O species, in an acidic aqueous solution. The RuIII OC complex was characterized by spectroscopic methods and DFT calculations. The oxidation state of the Ru center was shown to be close to +3; the Ru O bond showed a lower-energy Raman scattering at 732 cm 1 and the Ru O bond length was estimated to be 1.77(1) . The RuIII OC complex exhibits high reactivity in substrate oxidation under catalytic conditions; particularly, benzaldehyde and the derivatives are oxidized to the corresponding benzoic acid through C H abstraction from the formyl g...