Synthesis of N,N-Alkylated α-Tertiary Amines by Coupling of α-Aminoalkyltrifluoroborates and Grignard Reagents

The cross-coupling of alpha-aminoalkyltrifluoroborates and Grignard reagents to form N,N-substituted alpha-tertiary amines (ATAs) is reported. Key to the success of this reaction is the unexpected oxidation of the alpha-aminoalkyltrifluoroborate to the corresponding iminium cation by commercially available Barluenga's reagent. Various Grignard reagents added smoothly, enabling the synthesis of a variety of ATAs, which are of high value for medicinal chemistry and drug development. Many of the reported examples are not accessible by the established methods.