Palladium-Catalyzed Asymmetric Allylic Alkylations of Polynitrogen-Containing Aromatic Heterocycles

We report the palladium-catalyzed asymmetric allylic alkylation (AAA) reaction of a variety of nitrogen-containing aromatic heterocycles, including pyrazine, pyrimidine, pyridazine, quinoxaline, and benzoimidazole derivatives. The mesityl ester, whose steric bulk prevents competitive deacylation of the electrophile from "hard" nucleophiles, is introduced as a new leaving group in allylic alkylation chemistry. In contrast to our previous studies of AAA reactions with pyridine-based substrates, no precomplexation with a Lewis acid is required before deprotonation with LiHMDS, underscoring the relative acidity of these electron-deficient nucleophiles.