Concise Report
Photoredox-Catalyzed Metal-Free Regio- & Stereoselective C(sp2)–H Amination of Enamides with N-Aminopyridium Salts
Zheng-Bao Qin,
Kun Ni,
Li Wang,
Xiao-Di Wu,
Yu Zhang,
Kai Zhao,
Zheng-Bao Qin
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
These authors contributed equally.
Search for more papers by this authorKun Ni
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
These authors contributed equally.
Search for more papers by this authorLi Wang
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
Search for more papers by this authorXiao-Di Wu
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
Search for more papers by this authorYu Zhang
College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037 China
Search for more papers by this authorCorresponding Author
Kai Zhao
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
E-mail: [email protected]Search for more papers by this authorZheng-Bao Qin,
Kun Ni,
Li Wang,
Xiao-Di Wu,
Yu Zhang,
Kai Zhao,
Zheng-Bao Qin
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
These authors contributed equally.
Search for more papers by this authorKun Ni
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
These authors contributed equally.
Search for more papers by this authorLi Wang
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
Search for more papers by this authorXiao-Di Wu
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
Search for more papers by this authorYu Zhang
College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037 China
Search for more papers by this authorCorresponding Author
Kai Zhao
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu, 211816 China
E-mail: [email protected]Search for more papers by this authorComprehensive Summary
A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp2)–H amination of enamides with bench-stable and easily accessible N-aminopyridium salts is developed, affording synthetically and biologically prominent vicinal 1,2-diamine scaffolds with broad substrate scope and excellent functional group compatibility. The transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N-centered sulfonamidyl radical species to nucleophilic β-olefinic position of enamides followed by the ensuing single electron oxidation and β-H elimination, delivering geometrically-defined Z-configured β-sulfonamidylated enamides. The operational simplicity, environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives.
Supporting Information
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Appendix S1: Supporting Information |
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- 28Product 3va (CCDC 2277106) contains the crystallographic data for this paper. Other Z-configured enamides in Scheme 2 and Scheme 3 exhibit signals similar to 3va for its olefinic and benzylic hydrogens in 1H NMR.
- 29In consideration of the 81% deuterated ratio of 1a-d2, 0.185 mmol of 1a-d2 (a H-D mixture containing 81% deuterated enamide and 19% undeuterated one) was added along with 0.115 mmol of undeuterated enamide 1a in the same reaction vessel, so that the real amount of pure deuterated enamide (and its undeuterated competitor) was calculated to be 0.15 mmol approximately. The ratio of deuterated enamide 3aa-d1 vs 3aa in the isolated mixture was 34:66 as determined by 1H NMR, thus giving a calculated KH/KD = 0.66/0.34 = 1.94.
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