Anionic Chiral Co(III) Complexes Mediated Asymmetric Halocyclization─Synthesis of 5-Halomethyl Pyrazolines and Isoxazolines
Xiaobao Wu, Quan Gao, Junjie Fan, Zhenyu Zhao, Xue‐Qin Tu, Haiqun Cao, Jie Yu
Abstract
An asymmetric synthesis of 5-halomethyl pyrazolines and isoxazolines which bear a tertiary stereocenter by catalytic halocyclization of β,γ-unsaturated hydrazones and ketoximes is described. By using Brønsted acids of anionic chiral Co(III) complexes as catalysts, a variety of chiral 5-halomethyl pyrazolines and isoxazolines were obtained in good yields with high enantioselectivities (up to 99% yield, 97:3 er). Preliminary bioassay results indicated that several isoxazoline derivatives exhibited significant antifungal activities.
Topics & Concepts
StereocenterChemistryCatalysisYield (engineering)AntifungalCombinatorial chemistryOrganic chemistryMedicinal chemistryEnantioselective synthesisDermatologyMaterials scienceMedicineMetallurgySynthesis and Catalytic ReactionsVanadium and Halogenation ChemistryAsymmetric Synthesis and Catalysis