Copper-Catalyzed Asymmetric Formal [3 + 2] Cycloaddition of Propargylic Acetates with Hydrazines: Enantioselective Synthesis of Optically Active 2-Pyrazolines
作者:De-Yang Zhang、Long Shao、Jie Xu、Xiang-Ping Hu
DOI:10.1021/acscatal.5b01283
日期:2015.9.4
A catalytic asymmetric [3 + 2] cycloaddition of hydrazines to bis-electrophilic C3 synthons generated from propargylic acetates, followed by an intramolecular 1,3-H migration, for the regio- and enantioselective construction of chiral 2-pyrazolines has been reported. By employment of copper catalysis in combination with a structurally rigid tridentate P,N,N-ligand, a variety of chiral 2-pyrazolines
据报道,肼催化不对称的[3 + 2]环加成反应生成炔丙基乙酸酯生成的双亲电子C3合成子,然后在分子内进行1,3- H迁移,用于手性2-吡唑啉的区域和对映选择性构建。通过采用铜催化与结构刚性的三齿P,N,N-配体结合,可以以高收率和高对映选择性(高达96%ee)获得各种手性2-吡唑啉。已经提出了可能的过渡态来解释区域选择性和对映选择性的起源。