The research team of Ying Xia from the West China School of Public Health and West China Fourth Hospital recently made new progress in research on small ring asymmetric catalysis. The team published their findings in an online paper titled "Ni Catalyzed Tunable Enantioconvergence and Kinetic Resolution in the Coupling of Tertiary Cycles with Arylboroxines", in Angew. Chem. Int. ED , an authoritative journal in the field of chemistry. The first author of the paper is Dr. Xufei Yan, a postdoctoral fellow in the experimental center of the WCSPH, and Yulei Zhu, a Class 2021 graduate student, is the co first author. Ying Xia, a research fellow, is the corresponding author of the paper. The work unit of the paper is the WCSPH (West China Fourth Hospital)/State Key Laboratory of Biotherapy.
Chiralall-carbon quaternary stereocenteris widely present in natural substances, drugs, and bioactive molecules, and has always been a focus of attention in the field of chemistry.
“We report that a nickel catalyst system with a modified 1,1′-spirobiindane-7,7′-diol-phosphoramidite (SPINOL) as the chiral ligand can enable the coupling of tertiary cyclobutenols and arylboroxines in an enantioconvergent manner, providing cyclobutenes with an all-carbon quaternary stereocenter in good yields (up to 84 % yield) with excellent enantioselectivities (up to >99 % ee). Moreover, the catalytic system can be applied in the kinetic resolution of cyclobutenols under slightly modified conditions, giving enantioenriched tertiary cyclobutenols with ansfactor of up to >200. The reaction uses free hydroxyl groups as the leaving group without additional activation while the strained ring remains untouched. Preliminary mechanistic studies reveal that the inherent discrepant reactivity of the two enantiomers is the key to the controllable enantioconvergent and kinetic resolution process.”（Abstract）
This study is of guiding significance for the construction of chiral quaternary carbon in tension rings and the subsequent synthesis of tension ring molecules with multiple chiral centers.
The research work was funded by the National Natural Science Foundation of China (22001180) and the National High Level Talent Program. The relevant testing and analysis are mainly completed through high-performance liquid chromatography, 400 M nuclear magnetic resonance, and gas chromatography-mass spectrometry on the public experimental platform of the Public Health and Preventive Medicine Experimental Center.
https://onlinelibrary.wiley.com/doi/10.1002/anie.202304462
