Reactions of non-activated aryl halides with nucleophilic agents induced by alkali amides in liquid ammonia

Abstract

It has been shown that the reactions of nucleophiles with non-activated aryl halides, discovered by Bergstrom to be induced by alkali amides in liquid ammonia, proceed by way of a benzyne-type intermediate. The ease with which a given nucleophile can compete with amide ion does not appear to be a simple function of either its basic strength or nucleophilic character as measured in other reactions. Thus, the anions of a number of weak acids line up qualitatively in competitive power as follows: fluorenyl anion ∼ anilide > thiophenolate ∼ triphenylmethide > acetophenone enolate anion ∼ phenylacetylide > phenolate > pyrrolate > alkoxides, iodide or cynaide. The results indicate benzyne to be a highly unstable entity.