Liu Zhili, Ning Lichao, Yang Bingqian, Wang Kaixuan, Lin Lili, Feng Xiaoming
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University Chengdu 610064 P. R. China
Chem Sci. 2025 Aug 11. doi: 10.1039/d5sc04846j.
Ring-opening/cyclization represents a classic reaction of bicyclic diaziridines. In this study, an unprecedented ring-opening/migration cascade process was discovered in the reaction between bicyclic diaziridines and donor-acceptor (D-A) cyclopropanes. By employing a chiral ,'-dioxide/scandium(iii) complex as the catalyst, a diverse array of chiral dihydro-1-pyrazoles with a stereocenter in the side chain was efficiently synthesized featuring excellent ee values. Control experiments indicated that the substitution on the D-A cyclopropane is of critical importance in determining the cyclization or migration process. When combined with DFT calculations, a plausible reaction mechanism was proposed, which involves a key transition state. This work presents a novel method for accessing pyrazolines and broadens the scope of diaziridine chemistry.
开环/环化反应是双环二氮丙啶的经典反应。在本研究中，双环二氮丙啶与给体-受体（D-A）环丙烷之间的反应中发现了前所未有的开环/迁移串联过程。通过使用手性双噁唑啉/钪（III）配合物作为催化剂，高效合成了一系列侧链带有立体中心的手性二氢吡唑，对映体过量值优异。对照实验表明，D-A环丙烷上的取代基对于确定环化或迁移过程至关重要。结合密度泛函理论计算，提出了一个合理的反应机理，其中涉及一个关键过渡态。这项工作提出了一种获取吡唑啉的新方法，并拓宽了二氮丙啶化学的范围。
