1,4‐Addition of Bis(iodozincio)methane to α,β‐Unsaturated Ketones: Chemical and Theoretical/Computational Studies |
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Authors: | Mutsumi Sada Dr. Taniyuki Furuyama Dr. Shinsuke Komagawa Prof. Dr. Masanobu Uchiyama Prof. Dr. Seijiro Matsubara |
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Affiliation: | 1. Department of Material Chemistry, Graduate School of Engineering, Kyoudai‐katsura, Nishikyo, Kyoto 615‐8510 (Japan), Fax: (+81)?75‐383‐2461;2. The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351‐0198 (Japan);3. Current address: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7‐3‐1 Hongo, Bunkyo‐ku, Tokyo 113‐0033 (Japan) |
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Abstract: | 1,4‐Addition of bis(iodozincio)methane to simple α,β‐unsaturated ketones does not proceed well; the reaction is slightly endothermic according to DFT calculations. In the presence of chlorotrimethylsilane, the reaction proceeded efficiently to afford a silyl enol ether of β‐zinciomethyl ketone. The C? Zn bond of the silyl enol ether could be used in a cross‐coupling reaction to form another C? C bond in a one‐pot reaction. In contrast, 1,4‐addition of the dizinc reagent to enones carrying an acyloxy group proceeded very efficiently without any additive. In this case, the product was a 1,3‐diketone, which was generated in a novel tandem reaction. A theoretical/computational study indicates that the whole reaction pathway is exothermic, and that two zinc atoms of bis(iodozincio)methane accelerate each step cooperatively as effective Lewis acids. |
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Keywords: | addition reactions density functional calculations domino reactions ketones tandem reactions zinc |
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