Metalation neighboring group assistance

Standard organolithium reagents such as butyllithium, ec-butyllithium or tert-butyllithium deprotonate rapidly, if not instantaneously, the relatively acidic hydrocarbons of the 1,4-diene, diaryhnethane, triarylmethane, fluorene, indene and cyclopentadiene families and all terminal acetylenes (1-alkynes) as well. Butyllithium alone is ineffective toward toluene but its coordination complex with A/ ,A/ ,iV, iV-tetramethylethylenediamine does produce benzyllithium in high yield when heated to 80 To introduce metal into less reactive hydrocarbons one has either to rely on neighboring group-assistance or to employ so-called superbases. 

The neighboring group-assisted metalation of arenes and heterocycles is an area too vast to be included into this Chapter. Major aspects have been summarized in Chapter 10 of this book and a comprehensive, though still not exhaustive treatment of this theme can be found in a recent monograph. ... 

OH groups. With Lewis-acid catalysts alkoxide formation occurs on co-ordina-tively unsaturated metal sites, probably assisted by neighboring oxygen sites (Scheme 2). 

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