Abstract

Deprotonation of fluoroarenes carrying chlorine or bromine as addnl. substituents occurred always at a position adjacent to a fluorine if accomplished with potassium tert-butoxide activated butyllithium or lithium 2,2,6,6-tetramethylpiperidide. For example, treatment of 1-chloro-4-fluorobenzene with potassium tert-butoxide/butyllithium (superbase reagent) gave 5-chloro-2-fluorobenzoic acid (86% yield) as the major product and a small amt. of 2-chloro-5-fluorobenzoic acid. [on SciFinder (R)]

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