Two facile and effective C-3 arylation protocols of quinoxalin-2(1H)-ones with arylhydrazines and aryl boronic acids respectively via free radical cross-coupling reactions under metal-, photocatalyst- and light-free conditions have been unveiled. K2S2O8 has been used as an efficient oxidant to generate aryl radicals from arylhydrazines and aryl boronic acids under two different reaction conditions
已经揭示了喹喔啉-2( 1H )-酮分别与芳基肼和芳基硼酸通过自由基交叉偶联反应在金属、光催化剂和无光条件下进行的两种简便有效的C-3芳基化方案。 K 2 S 2 O 8已被用作有效的氧化剂,在两种不同的反应条件下由芳基肼和芳基硼酸生成芳基自由基。生成的芳基自由基在喹喔啉-2(1 H )-酮的C-3位发生自由基偶联反应,以良好至优异的产率产生3-芳基喹喔啉-2(1 H )-酮。 2,2,6,6-四甲基哌啶-1-氧基自由基捕获实验已证明自由基参与反应过程。
Biomimetic asymmetric reduction of benzoxazinones and quinoxalinones using ureas as transfer catalysts
作者:Zi-Biao Zhao、Xiang Li、Mu-Wang Chen、Zongbao K. Zhao、Yong-Gui Zhou
DOI:10.1039/d0cc03091k
日期:——
Using ureas as transfer catalysts through hydrogen bonding activation, biomimetic asymmetric reduction of benzoxazinones and quinoxalinones with chiral and regenerable NAD(P)H models was described, giving chiral dihydrobenzoxazinones and dihydroquinoxalinones with high yields and excellent enantioselectivities. A key dihydroquinoxalinone intermediate of a BRD4 inhibitor was synthesized using biomimetic
The first general, highlyenantioselectivehydrosilylation of benzoxazinones and quinoxalinones has been developed. The chiral Lewisbase organocatalysts that are readily accessible from (1S,2R)‐ephedrine and (1R,2S)‐ephedrine promoted the title reaction to afford various chiral dihydrobenzoxazinones and dihydroquinoxalinones with good yields as well as good enantioselectivities.
Biomimetic reduction of imines and heteroaromatics with chiral and regenerable [2.2]Paracyclophane-Based NAD(P)H model CYNAM
作者:Zhou-Hao Zhu、Yi-Xuan Ding、Yong-Gui Zhou
DOI:10.1016/j.tet.2021.131968
日期:2021.3
In our previous work, we reported the synthesis of chiral and regenerable [2.2]paracyclophane-derived NAD(P)Hmodels CYNAMs and their application in biomimetic asymmetric reduction of tetrasubstituted olefins. Herein, the biomimetic asymmetric reduction of imines and heteroaromatics has been successfully achieved using the chiral and regenerable CYNAMs and simple achiral phosphoric acid as the transfer