Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Lithium-hydrogen exchange with aromatic compounds

The insertion of elemental tellurium into C — Li or C — Na bonds is a convenient method for the preparation of alkali metal tellurolates. Many organic lithium compounds are commercially available or can be prepared, for instance, by halogen-lithium or hydrogen-lithium exchange. The reactions of the organic lithium compounds with elemental tellurium are performed in inert organic solvents such as diethyl other, tetrahydrofuran, tetrahydrofuran/hexane, or diethyl ether/benzene at temperatures (— 196° to + 20°) compatible with the stability of the organic lithium compound. The applicability of this reaction for the synthesis of aliphatic, aromatic, and heteroaromatic lithium tellurolates is documented in Table 1 (p. 155). [Pg.154]

Korneev and Kaufmann successfully lithiated 2-bromo-l,l-diphenylethylene (46) by bromide-lithium exchange to form 2-lithio-l,l-diphenylethylene (47). A second lithia-tion could be effected in four hours at room temperature by deprotonation of the aromatic ring with w-butyllithium in the presence of TMEDA (Scheme 17). Like in the synthesis of compound 23, the first lithiation activates the ortho-hydrogen atom of the Z-phenyl substituent to give 1,4-dilithium compound 48. In total, three equivalents of the alkyl-lithium base are required the third equivalent is consumed in the trapping reaction of w-bromobutane with generation of octane. [Pg.955]


See other pages where Lithium-hydrogen exchange with aromatic compounds is mentioned: [Pg.67]    [Pg.880]    [Pg.127]    [Pg.113]    [Pg.41]    [Pg.394]    [Pg.100]   
See also in sourсe #XX -- [ Pg.912 ]




SEARCH



Aromatic compounds hydrogenation

Aromatic hydrogen

Aromatic hydrogenation

Aromatics hydrogenation

Compounds hydrogen

Exchange compounds

Hydrogen aromaticity

Hydrogen-lithium exchange

Hydrogenated aromatics

Hydrogenated compounds

Hydrogenation compounds

Hydrogenous compounds

Lithium compounds

With aromatic compounds

© 2024 chempedia.info