Enantioselective Copper-Catalyzed [3 + 3] Cycloaddition of Tertiary Propargylic Esters with 1<i>H</i>-Pyrazol-5(4<i>H</i>)-ones toward Optically Active Spirooxindoles
作者:You-Wei Xu、Ling Li、Xiang-Ping Hu
DOI:10.1021/acs.orglett.0c03587
日期:2020.12.18
A copper-catalyzed enantioselective [3 + 3] cycloaddition of 3-ethynyl-2-oxoindolin-3-yl acetates with 1H-pyrazol-5(4H)-ones for the construction of optically active spirooxindoles bearing a spiro all-carbon quaternary stereocenter has been realized. With a combination of Cu(OTf)2 and chiral tridentate ketimine P,N,N-ligand as the catalyst, the reaction displayed broad substrate scopes, good yields
铜催化的3-乙炔基-2-氧代吲哚-3-基乙酸乙酸酯与1 H-吡唑-5(4 H)-的铜对映体选择性[3 + 3]环加成反应,用于构建带有螺全碳的旋光螺硫醇四元立体中心已实现。以Cu(OTf)2和手性三齿酮亚胺P,N,N-配体为催化剂,该反应显示出较宽的底物范围,良好的收率和高对映选择性。这代表了使用叔炔丙基酯作为双亲电子试剂进行手性螺环骨架的首次催化不对称炔丙基环加成反应。