Concise and efficient synthesis of 4-fluoro-1H-pyrrolo[2,3-b]pyridine.

ABSTRACT

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. [reaction see text]