Baston, EckhardMaggi, RaimondoFriedrich, KirstinSchlosser, Manfred2006-03-032006-03-032006-03-03200110.1002/1099-0690(200111)2001:21%3C3985::AID-EJOC3985%3E3.0.CO;2-Yhttps://infoscience.epfl.ch/handle/20.500.14299/226979Twofold H/metal interconversions (dimetalations) can be accomplished with spiny arenes (tert-butylbenzene, 1,4-di-tert-butylbenzene, 1,1,3,3-tetramethylindane and congeners) and N,N-crowded anilines (2,2,6,6-tetramethyl-1-phenylpiperidine and N,N-bis[triethylsilyl]aniline), albeit incompletely (av. and optimum yields of trapping products 25% and 41%, resp.). All the evidence points at an aggregate phenomenon. Dimetalation occurs only with an excess of a highly concd. butyllithium/K tert-butoxide mixt. in hydrocarbon media. In THF, no trace of a dimetalated species is found, although such species, once generated in a different manner, are moderately stable in this solvent at -75 Deg. 1,4-Dimetalloarenes are favored over the 1,3-isomers; 1,2-isomers do not form at all. As found by competition kinetics, 2,2,6,6-tetramethyl-1-phenylpiperidine and N,N-bis(triethylsilyl)aniline undergo monometalation at roughly the same rate as tert-butylbenzene and much more slowly than benzene does. [on SciFinder (R)]Aromatic hydrocarbons Role: RCT (Reactant)SPN (Synthetic preparation)PREP (Preparation)RACT (Reactant or reagent) (14-Dimetalloarenes; substitution effect on metalation rates of arenes by superbasic reagents); Acidity (effect on metalation ratesmetalation substituted arene crowded aniline superbasic reagent acidity effect; regiochem metalation substituted arene crowded aniline superbasic reagenttext::journal::journal article::research article