Concise and Efficient Synthesis of 4-Fluoro-1H-pyrrolo[2,3-b]pyridine

Two routes describing the preparation of 4-fluoro-1H-pyrrolo[2,3-b]pyridine (4a) from 1H-pyrrolo[2,3-b]pyridine N-oxide (1) are presented. Regioselective fluorination was achieved using either the Balz−Schiemann reaction or lithium−halogen exchange.