Science of Synthesis

Mordini, A.; Valacchi, M., Science of Synthesis, (2006) 8, 1228.

The o-, m-, and p-xylenes undergo mono- and even dimetalation by treatment with pentylsodium, although the yields of the corresponding dicarboxylic acids obtained following carbonation are quite low (19, 37, and 36%, respectively, for ortho-, meta-, and para-isomers).[‌8‌] If the pentylsodium–N,N,N′,N′-tetramethylethylenediamine reagent is used, o- and m-xylenes are both very efficiently converted into their dimetalated derivatives in quantitative yields; p-xylene furnishes only the monometalated product.[‌15‌,‌16‌] With the same reagent, an efficient double metalation of dimethylnaphthalenes has also been reported.[‌15‌,‌16‌] For example, dimetalation of 1,3-dimethylnaphthalene, followed by reaction with iodomethane, gives 1,3-diethylnaphthalene (‌2‌) in quantitative yield (‌Scheme 2‌).

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References

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• 8.Meeeee-Meee, (8888) M 88e, 888.