Directing Group Enabled Copper-Catalyzed Enantioselective S-Benzylation of Sulfenamides.

A copper-catalyzed radical relay strategy enables the enantioselective S-benzylation of sulfenamides using readily accessible benzylamine-derived Katritzky salts as benzyl radical precursors. A quinoline-based directing group proved advantageous for achieving high reactivity and enantioselectivity. This method afforded diverse chiral S-benzyl sulfilimines under mild conditions in up to 90% yield and 99% ee, with scale-up synthesis and derivatizations demonstrating synthetic utility.