Iron polypyridyl complex-catalyzed oxidative radical cyclization with nucleophilic α-amino radicals and electron-deficient olefins was achieved. Iron polypyridyl complexes have a range of redox potential (E1/2 = +0.82~1.10 V), which could oxidize tertiary amines, anilines and enamines (Eox = 0.8~1.0 V).1 One electron oxidation of tertiary amine by Fe(III) complex and further deprotonation of amine radical cation offers nucleophilic α-amino radical species, which is reactive to N-substituted maleimides and electron-deficient alkenes.2 Under optimal condition, we synthesized various tetrahydroquinoline derivatives. Additionally, the synthetic utility of this reaction was presented in the further transformation to pyrroloquinoline and tetrahydropyridazinedione of products.3 Herein, we present oxidative cycloaddition of tertiary amines with electron-deficient olefins under easy operation and high catalytic efficiency.
Acknowledgement
This work supported by the GRRC program of Gyeonggi province (GRRCKyungHee2017-A01) and National Research Foundation (NRF-2015R1D1A1A01060349).
Reference
1. a) Ju, X.; Li, D.; Li, W.; Yu, W.; Bian, F., Adv. Synth. Catal. 2012, 354, 3561. b) Comito, R. J.; Finelli, F. G.; MacMillan, D. W. C., J. Am. Chem. Soc. 2013, 135, 9358.
2. Zhu, S.; Das, A.; Bui, L.; Zhou, H.; Curran, D. P.; Reuping, M., J. Am. Chem. Soc. 2013, 135, 1823.
3. Nishino, M.; Hirano, K.; Satoh, T.; Miura, M., J. Org. Chem. 2011, 76, 6447.
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