Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula , often abbreviated as , where Ac is acetyl. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis.
Structure In the solid state the lead(IV) centers are coordinated by four acetate ions, which are bidentate, each coordinating via two oxygen atoms. The lead atom is 8 coordinate and the O atoms form a flattened trigonal dodecahedron.
Preparation It is typically prepared by treating of red lead with acetic acid and acetic anhydride (), which absorbs water. The net reaction is shown:
The remaining lead(II) acetate can be partially oxidized to the tetraacetate by Cl2, with a by-product:
Reagent in organic chemistry Lead tetraacetate is a strong oxidizing agent, a source of acetyloxy groups, and a general reagent for the preparation of organolead compounds. Some of its many uses in organic chemistry: Acetoxylation of benzylic, allylic, and α-oxygen ether C−H bonds, for example the conversion of dioxane to 2-acetoxy-1,4-dioxane Organic Syntheses, Vol. 82, p. 99 (2005) Article. An alternative reagent to bromine in Hofmann rearrangement Dehydrogenation of hydrazones and hydrazines, for example that of hexafluoroacetone hydrazone to bis(trifluoromethyl)diazomethane Cleavage of α-hydroxy acids or 1,2-diols to their corresponding aldehydes or ketones, often replacing ozonolysis; for instance, the oxidation of di-n-butyl -tartrate to n-butyl glyoxylate.Organic Syntheses, Coll. Vol. 4, p. 124 (1963); Vol. 35, p. 18 (1955) Article. Reaction with alkenes to form γ-lactones Oxidation of alcohols carrying a δ-proton to cyclic ethers.M B Smith, J March. March's Advanced Organic Chemistry (Wiley, 2001) () Oxidative cleavage of certain allyl alcohols in conjunction with ozone:Conversion of 1-allylcyclohexanol to cyclohexanone, in the proposed reaction mechanism the allyl group is first converted to a trioxalane according to conventional ozonolysis which then interacts with the alkoxy lead group. Transformation of 1,2-dicarboxylic acids or cyclic anhydrides to alkenes
Conversion of acetophenones to phenyl acetic acids Decarboxylation of carboxylic acids to alkyl halides in the Kochi reaction
Safety Lead(IV) acetate is toxic, because of lead. It is a neurotoxin. It badly affects the gum tissue, central nervous system, kidneys, blood, and reproductive system.
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