The regioselective homocoupling of meta-hydroxypyridines with hypervalent iodine(III).

The C - H homocoupling of meta-hydroxypyridines with phenyliodine(III) diacetate (PIDA) was carried out in dichloromethane at room temperature in the presence of cesium carbonate. The coupling reaction is highly regioselective with respect to the hydroxy group at the pyridine ring. Comparative control experiments with meta-alkoxypyridine suggest that the meta-hydroxy group at the pyridine ring plays a key role during the homocoupling reaction.