Stereoselective Synthesis of Pyrrolidines Containing a 3‑Fluoro Quaternary Stereocenter via Copper(I)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition

A highly efficient asymmetric 1,3-dipolar cycloaddition of azomethine ylides to β,β-disubstituted β-fluoroacrylates catalyzed by a chiral N,O-ligand/Cu­(CH3CN)4BF4 system is reported, affording chiral densely substituted pyrrolidines with four contiguous stereocenters, including one fluorinated quaternary stereocenter at the 3-position, in good to excellent yields (up to 99%), with excellent levels of diastereo- and enantioselectivities (dr >20:1; ee up to 99%).

本文报道了一种由手性N,O配体/四乙腈合铜(I)四氟硼酸盐（Cu(CH3CN)4BF4）催化的甲亚胺叶立德与β,β-二取代β-氟代丙烯酸酯之间的高效不对称1,3-偶极环加成反应。该反应可得到具有四个连续手性中心的手性高度取代吡咯烷类产物，其中3位包含一个含氟季手性中心，反应收率良好至优异（最高达99%），且展现出极佳的非对映选择性与对映选择性，非对映体比例（dr）>20:1，对映体过量值（ee）最高达99%。