Enantioselective Dearomatization of Pyridinium Salts by Copper‐Catalyzed C4‐Selective Addition of Silicon Nucleophiles

2024/11/06 by Xiao, Yao, Zhao, Zhi‐Yuan, Kemper, Sebastian +2
#500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften #asymmetric catalysis #copper #dearomatization #pyridinium salts #silicon

paper · doi:10.14279/depositonce-21660

Abstract

A copper‐catalyzed C4‐selective addition of silicon nucleophiles released from an Si−B reagent to prochiral pyridinium triflates is reported. The dearomatization proceeds with excellent enantioselectivity using Cu(CH3CN)4PF6 as the precatalyst and (R,R)‐Ph‐BPE (1,2‐bis[(2R,5R)‐2,5‐diphenylphospholan‐1‐yl]ethane) as the chiral ligand. A carbonyl group at C3 is required for this, likely acting a weak donor group to preorganize and direct the nucleophilic attack towards C4. The resulting 4‐silylated 1,4‐dihydropyridines can be further converted into functionalized piperidine derivatives.

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