Synthesis of pyridines by carbenoid-mediated ring opening of 2H-azirines

Roaming the range: The title reaction tolerates a wide range of substituents on the resulting pyridine ring using mild reaction conditions (see scheme; esp=α,α,α′,α′-tetramethyl-1,3-benzenedipropionic acid). The formation of the key intermediate is catalyst-controlled, and subsequent cyclization and oxidation affords pyridines in excellent yields. The method has been used for the efficient synthesis of polyarylpyridines