N-Heterocyclic Carbene-Catalyzed Radical Relay Enabling Synthesis of δ-Ketocarbonyls

An NHC-catalyzed radical relay enabled the vicinal alkylacylation of alkenes using aldehydes and tertiary alpha-bromo esters as a versatile route to delta-keto esters bearing an all-carbon quaternary center at the position alpha to the ester. The protocol was applicable to the reaction of tertiary alpha-bromoamides to afford delta-keto amides. This protocol enabled the conversion of readily available starting materials to congested and functionalized delta-ketocarbonyls in a single step without using transition metals.