Iron-Catalyzed Highly Enantioselective Hydrogenation of Alkenes
Peng Lu, Xiang Ren, Haofeng Xu, Dongpo Lu, Yufeng Sun and Zhan Lu*
*Department of Chemistry, Zhejiang University, 310058 Hangzhou, China, Email: luzhanzju.edu.cn
P. Lu, X. Ren, H. Xu, D. Lu, Y. Sun, Z. Lu, J. Am. Chem. Soc., 2021, 143, 12433-12438.
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An iron-catalyzed highly enantioselective hydrogenation of minimally functionalized 1,1-disubstituted alkenes provides chiral alkanes with full conversion and excellent ee using 1 atm of hydrogen gas and a chiral 8-oxazoline iminoquinoline ligand. This protocol is operationally simple and shows good functional group tolerance.
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General procedure for asymmetric hydrogenation of 1,1-disubstituted alkenes:
A 25 mL flame-dried Schleck flask was cooled at room temperature under nitrogen and charged with catalyst (0.025 mmol), alkene (0.50 mmol), hydrosilane (0.10 mmol). The system was purged one time, acetonitrile (0.10 mmol) and dry toluene (1 mL) were added successively. Then, NaBHEt3 (1 M in THF) (75 μL, 0.075 mmol) was injected slowly, the reaction was stirred 5 min, a balloon with hydrogen was added and the system was purged three times. The mixture was stirred for 12 hours at room temp. The reaction was quenched with PE. The mixture was filtered through a pad of silica gel and washed with PE (50 mL). The filtrate was concentrated without further purification to afford the corresponding product.