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 α-bromo esters as a versatile route to δ-keto esters bearing an all-carbon quaternary center at the position α to the ester. The protocol was applicable to the reaction of tertiary α-bromoamides to afford δ-keto amides. This protocol enabled the conversion of readily available starting materials to congested and functionalized δ-ketocarbonyls in a single step without using transition metals.