Bronsted acid-catalysed conjugate addition of photochemically generated alpha-amino radicals to alkenylpyridines

The conjugate addition of alpha-amino radicals to alkenylpyridines has been accomplished by the synergistic merger of Bronsted acid and visible light photoredox catalysis. Key to reaction development was the protonation of the alkenylpyridines that transiently generated a highly reactive, electrophilic pseudo-iminium ion intermediate. Initial investigations using chiral phosphoric acids provide clues on the feasibility of an enantioselective catalytic variant.