- Facilitating Ir-Catalyzed C-H Alkynylation with Electrochemistry: Anodic Oxidation-Induced Reductive Elimination
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An electrochemical approach in promoting directed C-H alkynylation with terminal alkyne via iridium catalysis is reported. This work employed anodic oxidation of Ir(III) intermediate (characterized by X-ray crystallography) to promote reductive elimination, giving the desired coupling products in good yields (up to 95%) without the addition of any other external oxidants. This transformation is suitable for various directing groups with H2 as the only byproduct, which warrants a high atom economy and practical oxidative C-C bond formation under mild conditions.
- Shan, Chuan,Shi, Xiaodong,Wang, Chenhuan,Wei, Jingwen,Wojtas, Lukasz,Xie, Yan,Ye, Xiaohan,Zhang, Shuyao
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p. 11693 - 11699
(2020/11/27)
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- Rh(III)- and Ir(III)-Catalyzed C-H alkynylation of arenes under chelation assistance
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An efficient Rh(III)- and Ir(III)-catalyzed, chelation-assisted C-H alkynylation of a broad scope of (hetero)arenes has been developed using hypervalent iodine-alkyne reagents. Heterocycles, N-methoxy imines, azomethine imines, secondary carboxamides, azo compounds, N-nitrosoamines, and nitrones are viable directing groups to entail ortho C-H alkynylation. The reaction proceeded under mild conditions and with controllable mono- and dialkynylation selectivity when both mono- and dialkynylation was observed. Rh(III) and Ir(III) catalysts exhibited complementary substrate scope in this reaction. The synthetic applications of the coupled products have been demonstrated in subsequent derivatization reactions. Some mechanistic studies have been conducted, and two Rh(III) complexes have been established as key reaction intermediates. The current C-H alkynylation system complements those previously reported under gold or palladium catalysis using hypervalent iodine reagents.
- Xie, Fang,Qi, Zisong,Yu, Songjie,Li, Xingwei
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supporting information
p. 4780 - 4787
(2014/04/17)
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