Pyridinium Design for Deaminative Reactions of Sterically Encumbered Alkyl Amines

We introduce a new 3,5-diphenylpyridinium motif that can be readily installed on α-tertiary alkyl amines and enables effective deamination. This advance overcomes the limitation that Katritzky pyridinium salts cannot be accessed from α-tertiary alkyl amines. Use of this 3,5-diphenylpyridinium salt enables a nickel-catalyzed reductive alkylation of Michael acceptors to construct quaternary carbons with a broad range of tertiary alkyl groups. Density functional theory (DFT) calculations were used to understand the surprising reactivity difference between adamantyl and other tertiary alkyl groups.