Copper‐Catalyzed Asymmetric Cyanation of Propargylic Radicals Derived From Silyl‐Substituted Allenes and Alkynes

Here, we report an efficient method to synthesize enantiomerically enriched propargyl nitriles via copper-catalyzed asymmetric cyanation of propargylic radicals, which are generated from silyl-substituted allenes or alkynes. These reactions proceeded through a highly site-selective hydrogen atom abstraction (HAA) with Cu(II)-bound nitrogen-centered radicals (NCRs). Notably, silyl-substituted allenes demonstrate exceptional allenic sp² C─H bond activation selectivity, outcompeting alternative reactive sp³ C─H bonds (benzylic, allylic, and heteroatom-adjacent) in HAA processes. This chemo-selectivity profile enables precise enantiocontrol and site-specific functionalization of complex molecular architectures.