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Phenyllithium is an organometallic agent with the empirical formula C 6 H 5 Li. It is most commonly used as a metalating agent in organic syntheses and a substitute for Grignard reagents for introducing phenyl groups in organic syntheses. [ 3 ]
Organolithium reagents provide a wide range of basicity. tert-Butyllithium, with three weakly electron donating alkyl groups, is the strongest base commercially available (pKa = 53). As a result, the acidic protons on −OH, −NH and −SH are often protected in the presence of organolithium reagents.
The reactivity of these five classes of compounds covers a broad range; the relative reaction rates of acid chlorides and amides differ by a factor of 10 13. [ 2 ] A major factor in determining the reactivity of acyl derivatives is leaving group ability, which is related to acidity.
Phenyl groups are usually introduced using reagents that behave as sources of the phenyl anion or the phenyl cation. Representative reagents include phenyllithium (C 6 H 5 Li) and phenylmagnesium bromide (C 6 H 5 MgBr). Electrophiles are attacked by benzene to give phenyl derivatives: + + + +
Pentaphenylphosphorus can be formed by the action of phenyllithium on tetraphenylphosphonium bromide or tetraphenylphosphonium iodide. [3] The compound was produced during the course of Wittig's Nobel-prize-winning investigations of organophosphorus compounds.
The erythro betaine can be converted to the threo betaine using phenyllithium at low temperature. [18] This modification affords the E-alkene. The Schlosser variant of the Wittig reaction. Allylic alcohols can be prepared by reaction of the betaine ylide with a second aldehyde. [19] For example: An example of the Schlosser variant of the Wittig ...
The negative charges create a repulsion that causes the polymer to swell. This swelling behavior is observed when the pH is greater than the pKa of the polymer. [2] Examples include polymethyl methacrylate polymers (pharmacologyonline 1 (2011)152-164) and cellulose acetate phthalate.
Adding phenyllithium slowly to a mixture of 6 and chloromethyl benzyl ether in excess in THF at 78 °C gave the benzylgliotoxin adduct 7 at 45% yield. Next, boron trichloride treatment of 7 in in methylene chloride at 0 °C yielded the gliotoxin anisaldehyde adduct 8 at 50% yield.