General methods for the highly site-selective Suzuki monocoupling of 3,5-dichloropyridazines have been discovered. By changing the ligand employed, the preferred coupling site can be switched from the 3-position to the 5-position, typically considered the less reactive C–X bond. These conditions are applicable to the coupling of a wide variety of aryl-, heteroaryl-, and vinylboronic acids with high
Here we report the first example of the dimerisation of azirines to 2H-imidazoles or 3,5-disubstituted pyridazines from a reaction promoted by FeCl2. An azirine complex with a radical structure is proposed as an intermediate. Cyclopropyl ketones and pyrrolines are isolated when the reaction is carried out in the presence of styrenes.