Monometallic organolithium reagents

As outlined in the following text, the halogen/metal exchange is an equilibrium, and thus the position of the equilibrium depends on the basicity of the exchange reagent, fert-butyllithium outperforms 5ec-butylhthium, which is superior to butyUithium. Methylhthium is the least reactive alkyhithium reagent but can stiU be more effective than phenylhthium in some cases  

Hetero-substituents such as dialkylamino or bis(trialkylsilyl)amino, alkoxy and 2-tetrahydro-pyranyloxy, lithiooxy or lithiooxycarbonyl, fluoro or trifluoromethyl, and chloro are well tolerated. Cyano or nitro and bromo or iodo substituents are tolerated when the solvent and temperature are carefully chosen [3]. 

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