Chiral Iridium Complexes of Anionic NCP Pincer Ligand for Asymmetric Transfer Hydrogenation of 1,1-Diarylethenes with Ethanol
Lu Qian, Xixia Tang, Zhidao Huang, Yulei Wang, Guixia Liu* and Zheng Huang*
*Shanghai Institute of Organic Chemistry, University of Chinese Academy
of Sciences, CAS, 345 Lingling Road, Shanghai 200032, China,
Email: guixia
sioc.ac.cn, huangzhsioc.ac.cn
L. Qian, X. Tang, Z. Huang, Y. Wang, G. Liu, Z. Huang, Org. Lett., 2021, 23, 8978-8983.
DOI: 10.1021/acs.orglett.1c03455
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Abstract
Chiral iridium complexes ligated by anionic oxazoline-bearing NCP-type pincer ligands enable an asymmetric transfer hydrogenation (ATH) of diarylethenes using environmentally benign ethanol as the hydrogen donor. High enantioselectivities could be achieved for substrates bearing ortho-Me, ortho-Cl, or ortho-Br substituents on one of the aryl groups.
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General Procedure for Asymmetric Transfer Hydrogenation of 1,1-Diarylethenes with EtOH
In an argon filled glovebox, catalyst (10 μmol, 7.46 mg), NaOtBu (15 μmol, 1.44 mg), alkene (0.25 mmol) and EtOH (0.2 mL) were added to a 10 mL dried Schlenk tube. The tube was sealed with a Teflon plug and the mixture was stirred at room temperature for 36h. The reaction was quenched by exposure to air. The resulting mixture was concentrated in vacuum and the residue was purified by chromatography (PE/EA = 50:1-10:1) on silica gel.
L. Qian, C. Yu, L. Gan, X. Tang, Y. Wang, G. Liu, X. Leng, Z. Sun, Y. Guo, X.-S. Xue, Z. Huang, J. Am. Chem. Soc., 2024, 146, 3427-3437.
Iridium-Catalyzed Asymmetric Transfer Hydrogenation of 1-Aryl-1-alkylethenes with Ethanol
X. Tang, L. Qian, G. Liu, Z. Huang, Org. Lett., 2023, 25, 4950-4954.
Key Words
ID: J54-Y2021
