胍-脲双功能有机催化剂催化 1,4-萘醌的不对称环氧化反应。
Asymmetric Epoxidation of 1,4-Naphthoquinones Catalyzed by Guanidine-Urea Bifunctional Organocatalyst.
机构信息
Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , 2-24-16, Naka-cho , Koganei city , 184-8588 , Tokyo , Japan.
Department of Chemistry and Research Center for Smart Molecules, Faculty of Science , Rikkyo University , 3-34-1, Nishi-Ikebukuro , Toshima-ku , 171-8501 , Tokyo , Japan.
出版信息
Org Lett. 2018 May 18;20(10):2811-2815. doi: 10.1021/acs.orglett.8b00641. Epub 2018 May 2.
An enantioselective nucleophilic epoxidation of 2-substituted 1,4-naphthoquinones in the presence of a newly developed guanidine-bisurea bifunctional organocatalyst with tert-butyl hydroperoxide (TBHP) as an oxidant is presented. 1,4-Naphthoquinones bearing substituents at C6, C7, and C2 were available for the reaction, and the corresponding epoxides were obtained with 88:12-95:5 er in 71-98% yields. DFT calculations indicated that substituents at C2 and C6 in the terminal Ar group of the catalyst 9k play a key role in controlling the stereochemical outcome.
本文报道了在新型胍-双脲双功能有机催化剂的存在下，用过氧化叔丁醇（TBHP）作为氧化剂，对 2-取代 1,4-萘醌进行对映选择性亲核环氧化反应。6、7 和 2 位取代基的 1,4-萘醌可参与反应，相应的环氧化物以 88:12-95:5 的对映选择性和 71-98%的产率得到。DFT 计算表明，催化剂 9k 末端 Ar 基团中 C2 和 C6 上的取代基在控制立体化学结果方面起着关键作用。
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