Dehydrogenative coupling reactions catalysed by Rose Bengal using visible light irradiation

Rose Bengal, an organic dye, was demonstrated to be a photoredox catalyst for dehydrogenative coupling reactions using visible light irradiation. alpha-Functionalised tertiary amines were obtained with good to excellent yields. Air is essential for this reaction and acts as the terminal oxidant. This is an environmentally friendly C-H functionalisation methodology that avoids the use of metal catalysts and stoichiometric amount of peroxo-compounds.