Acid-Catalyzed Regioselective 1,6-Conjugate Addition of Mercaptopyridine/Hydroxypyridine to Para-Quinone Methides

Abstract This protocol describes a trifluoroacetic acid-catalyzed regioselective 1,6-conjugate addition of mercaptopyridine and hydroxypyridine to para-quinone methides. The present reactions exhibit superior results in terms of regioselectivity, mild reaction conditions, straightforward workup (no column chromatography purification), and broad substrate scope with good functional-group compatibility. This efficient method enables the synthesis of trisubstituted methanes with pyridone and sulfide core structures.