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Journal article

Selective mono- or dimetalation of arenes by means of superbasic reagents

If employed in THF, stoichiometric amts. of BuLi and KOCMe3 react with benzene to give clean monometalation. In hexane suspension, however, considerable amts. of meta and para-disubstituted byproducts are obtained (approx. 10%). They become preponderant if a 3-fold excess of the metalating agent is used. Naphthalene, under the same conditions, gives a mixt. of two mono- and ten disubstituted derivs. Alkyl groups, as present in tert-butylbenzene, retard the metalation at both m- and p-positions, while trialkylsilyl groups deactivate only m-positions. In either case exclusive monosubstitution occurs. Perdeuteriobenzene undergoes metalation and subsequent electrophilic mono- or disubstitution to afford isotopically labeled compds. with moderate, though synthetically attractive yields. The kinetic isotope effects and product ratios can be taken as evidence for aggregate formation at the level of both the superbasic metalating reagent and the organometallic intermediates. [on SciFinder (R)]

    Keywords: Isotope effect (in metalation of arenes with superbasic reagents ; of deuterium); Aromatic hydrocarbons Role: RCT (Reactant) ; RACT (Reactant or reagent) (metalation of ; with superbasic reagents ; regiochem. of); Metalation (of arenes with superbasic reage ; metalation arene superbasic reagent regiochem; isotope effect metalation arene deuterium; benzene metalation superbasic reagent regiochem

    Note:

    CAN 114:23527

    25-24

    Benzene, Its Derivatives, and Condensed Benzenoid Compounds

    Inst. Chim. Org.,Univ. Lausanne,Lausanne,Switz.

    Journal

    0040-4020

    written in English.

    7782-39-0 (Deuterium) Role: PRP (Properties) (isotope effect of, in metalation of benzene or toluene with superbasic reagent); 865-47-4 (Potassium tert-butoxide) Role: RCT (Reactant), RACT (Reactant or reagent) (metalation by, of arenes, in combination with butyllithium); 109-72-8 (Butyllithium) Role: RCT (Reactant), RACT (Reactant or reagent) (metalation by, of arenes, in combination with potassium tert-butoxide); 108-88-3 (Toluene); 2037-26-5 Role: RCT (Reactant), RACT (Reactant or reagent) (metalation of, with superbasic reagent, kinetic isotope effect in); 71-43-2 (Benzene); 91-20-3 (Naphthalene); 98-06-6 (tert-Butylbenzene); 1014-60-4 (1,3-Di-tert-butylbenzene); 1076-43-3 (Perdeuteriobenzene) Role: RCT (Reactant), RACT (Reactant or reagent) (metalation of, with superbasic reagent, regiochem. of); 13154-24-0 (Chlorotriisopropylsilane) Role: RCT (Reactant), RACT (Reactant or reagent) (phenylation of); 2214-14-4P (1-Methyl-1-phenylcyclopropane); 17903-14-9P (Triisopropylphenylsilane) Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and metalation of, with superbasic reagent, regiochem. of); 98-73-7P; 7498-54-6P (3-tert-Butylbenzoic acid); 16225-26-6P; 131170-39-3P; 131170-40-6P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, via metalation of alkylbenzene with superbasic reagent); 65-85-0P (Benzoic acid); 100-21-0P (1,4-Benzenedicarboxylic acid); 121-91-5P (1,3-Benzenedicarboxylic acid); 768-32-1P (Trimethylphenylsilane); 2060-89-1P (1,3-Bis(trimethylsilyl)benzene); 13183-70-5P (1,4-Bis(trimethylsilyl)benzene) Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, via metalation of benzene with superbasic reagent); 1079-02-3P (Benzoic-d5 acid); 4165-62-2P (Phen-d5-ol); 14132-51-5P (Benzaldehyde-2,3,4,5,6-d5); 17901-93-8P (Benzaldehyde-d6); 25294-85-3P (1,4-Benzene-2,3,5,6-d4-diol); 60088-54-2P (1,4-Benzene-2,3,5,6-d4-dicarboxylic acid); 131170-43-9P (1,3-Benzene-2,4,5,6-d4-dicarboxaldehyde); 131170-44-0P (1,4-Benzene-2,3,5,6-d4-dicarboxaldehyde) Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, via metalation of perdeuteriobenzene with superbasic reagent); 131170-41-7P; 131170-42-8P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, via metalation of triisopropylphenylsilane with supberbasic reagent); 3591-42-2 Role: RCT (Reactant), RACT (Reactant or reagent) (redn. of, with sodium)

    Reference

    • LSCO-ARTICLE-1990-010

    Record created on 2006-03-03, modified on 2016-08-08

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