A method for synthesizing aromatic compounds by selectively dehalogenating aromatic starting materials is provided. Compounds may be prepared which are substituted with fluoro, chloro or bromo. The method may be used to remove halogen atoms from sites at which halogenation is not desired, and to form substantially pure halogenated compounds from mixtures of starting materials. The method uses a copper containing dehalogenation agent and an acid with the dehalogenation being controlled by a substituent such as a carboxylic acid, amide, ester, aldehyde, ketone or cyano on the aromatic ring.
Disclosed are compounds of Formula 1, including all stereoisomers, N-oxides, and salts thereof, wherein X1, X2, X3, n and P are as defined in the disclosure. Also disclosed are compositions containing the compounds of Formula 1 and methods for controlling undesired vegetation comprising contacting the undesired vegetation or its environment with an effective amount of a compound or a composition of the invention.