Redox-neutral ketone-olefin coupling enabled by mild ketone-to-ketyl-type radical conversion.

Source: PubMed, NCBI / U.S. National Library of Medicine

Ketones are ubiquitous functional groups and serve as versatile synthetic handles. However, a long-standing challenge in ketone chemistry is the lack of mild, broadly compatible approaches for converting common aliphatic ketones into ketyl-type radicals, especially those circumventing strongly reductive conditions and/or reagents. This limitation has hindered the development of unconventional ketone transformations, particularly the integration of ketyl-type radical generation with transition-metal catalysis for valuable C-C bond formation at carbonyl carbons. Here we report an efficient, mild protocol that converts aliphatic ketones to ketyl-type radicals via a bifunctional silyl reagent. Leveraging a distinct radical translocation strategy, our approach bypasses strongly reductive conditions and enables its merger with Pd catalysis to unlock redox-neutral ketone-olefin couplings. Diverse alkenylation and allylation products were obtained using readily available olefins instead of organometallic reagents, with broad functional group tolerance. Both inter- and intramolecular variations were developed, and this adaptable ketone-to-ketyl-type radical platform may provide access to other valuable ketone transformations.