Asymmetric Epoxidation of 1,4-Naphthoquinones Catalyzed by Guanidine‐Urea Bifunctional Organocatalyst
Asymmetric Epoxidation of 1,4-Naphthoquinones Catalyzed by Guanidine‐Urea Bifunctional Organocatalyst
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胍-脲双功能有机催化剂催化1,4-萘醌不对称环氧化反应
DOI：
10.1021/acs.orglett.8b00641
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发表时间：
2018
期刊：
影响因子：
5.2
通讯作者：
Nagasawa Kazuo
中科院分区：
文献类型：
--
作者：
Kawaguchi Masaki;Nakano Katsuhiro;Hosoya Keisuke;Orihara Tatsuya;Yamanaka Masahiro;Odagi Minami;Nagasawa Kazuo
本文报道了以叔丁基氢过氧化氢(TBHP)为氧化剂，在一种新的双功能有机催化剂的催化下，2-取代1，4-萘醌的不对称亲核环氧化反应。反应可用C6、C7和C2取代的1，4-萘醌类化合物进行，得到相应的环氧化物，产率为88：12-95：5，产率71-98%。密度泛函理论计算表明，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产物中起着关键作用。
An enantioselective nucleophilic epoxidation of 2-substituted 1,4-naphthoquinones in the presence of a newly developed guanidine–bisurea bifunctional organocatalyst withtert-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 88:12–95:5erin 71–98% yields. DFT calculations indicated that substituents at C2 and C6 in the terminal Ar group of the catalyst9kplay a key role in controlling the stereochemical outcome.