Palladium-Catalyzed Substitutions of Allylic Nitro Compounds. Regiochemistry

Primary, secondary, and tertiary allylic nitro compounds underwent Pd(0)-catalyzed allylic substitution by stabilized carbanions, secondary amines, and benzenesulfinate ion (PhSO₂~). α-nitro olefins also behaved as allylic nitro compounds, via base-catalyzed vinyl allyl rearrangement, and underwent allylic substitution by secondary amines and The regiochemistry of these substitutions was dependent on the structure of the allylic nitro compound and on the steric bulk of the nucleophile. Generally, substitution occurred at the less hindered or least substituted site. In some cases added or generated NaNO₂affected the regioselectivity of the allylic substitution of allylic nitro compounds and some allylic acetates by PhSO₂‘. Under these conditions, the more sterically hindered allylic sulfones were formed.