In recent years, the merging of electrosynthesis with 3d metal catalyzed CÀ H activation has emerged as a sustainable and powerful technique in organic synthesis. Despite the impressive advantages, the development of an enantioselective version remains elusive and poses a daunting challenge. Herein, we report the first electrooxidative cobalt-catalyzed enantio-and regioselective CÀ H/NÀ H annulation with olefins using an undivided cell at room temperature (up to 99 % ee). t Bu-Salox, a rationally designed Salox ligand bearing a bulky tert-butyl group at the ortho-position of phenol, was found to be crucial for this asymmetric annulation reaction. A strong cooperative effect between t Bu-Salox and 3,4,5-trichloropyridine enabled the highly enantioand regioselective CÀ H annulation with the more challenging α-olefins without secondary bond interactions (up to 96 % ee and 97 : 3 rr). Cyclovoltametric studies, and the preparation, characterization, and transformation of cobaltacycle intermediates shed light on the mechanism of this reaction.
Pyridine derivatives R 0380 Pd(II)-Catalyzed Enantioselective Activation of C(sp 2 )-H and C(sp 3 )-H BondsUsing Monoprotected Amino Acids as Chiral Ligands. -Amino acid MAA provides the best results concerning the ortho-alkylation of racemic pyridyl diarylmethanes. The alkylation at the aliphatic bond in substrate (VI) proceeds poorly; the best results are achieved using CPA as a catalyst. -(SHI, B.-F.; MAUGEL, N.; ZHANG, Y.-H.; YU*, J.-Q.; Angew. Chem., Int. Ed. 47 (2008) 26, 4882-4886; Dep. Chem., Scripps Res. Inst.,
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