Publication

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

Manfred Schlosser
1990
Journal Articles

Abstract

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)]

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https://infoscience.epfl.ch/entities/publication/e6247d1f-cfa3-4b7d-90ce-ed23a52e0334

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Manfred Schlosser
1990
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/e6247d1f-cfa3-4b7d-90ce-ed23a52e0334

About this result

Related concepts (16)

Organometallic chemistry

Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well.

Group 2 organometallic chemistry

Group 2 organometallic chemistry refers to the chemistry of compounds containing carbon bonded to any group 2 element. By far the most common group 2 organometallic compounds are the magnesium-containing Grignard reagents which are widely used in organic chemistry. Other organmetallic group 2 compounds are rare and are typically limited to academic interests. As the group 2 elements (also referred to as the alkaline earth metals) contain two valence electrons, their chemistries have similarities group 12 organometallic compounds.

Pyrrole

Pyrrole is a heterocyclic, aromatic, organic compound, a five-membered ring with the formula . It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, . Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme. Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme, the chlorins, bacteriochlorins, and chlorophylls.