Asymmetric Construction of α,γ-Disubstituted α,β-Butenolides Directly from Allylic Ynoates Using a Chiral Bifunctional Phosphine Ligand Enables Cooperative Au Catalysis
Ting Li*, Shicheng Dong, Conghui Tang, Meiling Zhu, Nan Wang, Weiguang Kong, Wenchao Gao, Jun Zhu* and Liming Zhang*
*Nanyang Normal University, Henan 473061, China; Xiamen
University, Xiamen 361005, China; UCLA, Santa Barbara, CA 93106, USA,
Email: chemlt2015
nynu.edu.cn, jun.zhuxmu.edu.cn,
zhangchem.ucsb.edu
T. Li, S. Dong, C. Tang, M. Zhu, N. Wang, W. Kong, W. Gao, J. Zhu, L. Zhang, Org. Lett., 2022, 24, 4427-4432.
DOI: 10.1021/acs.orglett.2c01652
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Abstract
A cationic gold(I) catalyst featuring a chiral bifunctional phosphine ligand mediates a highly efficient construction of γ-substituted α-allyl-α,β-butenolides with up to >99% enantiomeric excess from readily available allylic ynoates.
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General Procedure:
Dry DCE (2 mL), allylic ynoate (0.2 mmol), (S)-LAuCl (9mg, 5% mmol), NaBARF (35.4mg, 20% mmol) and 5Å MS (250 mg) were added to an oven-dried argon protected flask. The reaction was then heated at 80 °C (heating mantle) monitored by TLC. Upon completion, the reaction was concentrated under reduced pressure. The residue was purified by flash column chromatography (eluents: hexanes and ethyl acetate) to afford pure product.
X. Cheng, T. Li, K. Gutman, L. Zhang, J. Am. Chem. Soc., 2021, 143, 10876-10881.
Key Words
ID: J54-Y2022
