Iron‐Catalyzed Highly Enantioselective cis‐Dihydroxylation of Trisubstituted Alkenes with Aqueous H2O2

• DOI: 10.1002/ange.202002866
• Publication Date: 2020-06-05T04:16:10Z
• Authors: Jinhu Wei; Liangliang Wu; Hai‐Xu Wang; Xiting Zhang; Chun‐Wai Tse; Cong‐Ying Zhou; Jie‐Sheng Huang; Chi‐Ming Che
• Keywords: Dihydroxylation; Alkene

Abstract Reliable methods for enantioselective cis ‐dihydroxylation of trisubstituted alkenes are scarce. The iron(II) complex ‐α‐[Fe II (2‐Me 2 ‐BQPN)(OTf) ], which bears a tetradentate N 4 ligand (Me ‐BQPN=( R , )‐ N′ ‐dimethyl‐ ‐bis(2‐methylquinolin‐8‐yl)‐1,2‐diphenylethane‐1,2‐diamine), was prepared and characterized. With this as the catalyst, broad range electron‐deficient were efficiently oxidized to chiral ‐diols in yields up 98 % 99.9 ee when using hydrogen peroxide (H O ) oxidant under mild conditions. Experimental studies (including 18 O‐labeling, ESI‐MS, NMR, EPR, UV/Vis analyses) DFT calculations performed gain mechanistic insight, suggested possible involvement ‐Fe V (O) reaction intermediate an active oxidant. This ‐[Fe (chiral ligand)] 2+ /H method could be viable green alternative/complement existing OsO ‐based asymmetric alkene dihydroxylation reactions.