Selective activation of the benzylic C(sp3)–H bond is pivotal for the construction of complex organic frameworks. Achieving precise selectivity among C–H bonds with comparable energetic and steric profiles remains a profound synthetic challenge. Herein, we unveil a site- and stereoselective benzylic C(sp3)–H alkenylation utilizing metallaphotoredox catalysis. Various linear and cyclic (Z)-all-carbon tri- and tetrasubstituted olefins can be smoothly obtained. This strategy can be applied to complex substrates with multiple benzylic sites, previously deemed unsuitable due to the uncontrollable site-selectivity. In addition, sensitive functional groups such as terminal alkenyl and TMS groups are compatible under the mild conditions. The exceptional site-selectivity and broad substrate compatibility are attributed to the visible-light catalyzed relay electron transfer–proton transfer process. More importantly, we have extended this methodology to achieve enantioselective benzylic C(sp3)–H alkenylation, producing highly enantioenriched products. The applicability and scalability of our protocol are further validated through late-stage functionalization of complex structures and gram-scale operations, underscoring its practicality and robustness.
This article is Open Access
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