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The Criegee oxidation is a glycol cleavage reaction in which vicinal diols are oxidized to form ketones and aldehydes using lead tetraacetate. It is analogous to the use of periodate (Malaprade reaction) but uses a milder oxidant. This oxidation was discovered by Rudolf Criegee and coworkers and first reported in 1931 using ethylene glycol as ...
Another reagent is lead tetraacetate (Pb(OAc) 4). [4] These I- and Pb-based methods are called the Malaprade reaction and Criegee oxidation, respectively. The former is favored for aqueous solutions, the latter for nonaqueous solutions. [1] Cyclic intermediate are invariably invoked. The ring then fragments, with cleavage of the carbon–carbon ...
Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula Pb(C 2 H 3 O 2) 4. 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. [2]
It was also observed, that the addition of lead tetraacetate can facilitate the Stieglitz rearrangement of amine derivatives. [32] After the formation of the activated amine derivative intermediate by coordination to the lead center, the following rearrangement again proceeds via migration of the aromatic group under formation of a C–N bond ...
In the absence of a hydrogen on the δ-carbon, or when the particular conformation of the substrate orients the ε-carbon close together, 1,6-hydrogen atom transfer is the favored process. However, these reactions tend to be an order of magnitude slower than the corresponding 1,5-hydrogen atom transfer.
The mechanism of carbonyl oxidation by iodine(III) reagents varies as a function of substrate structure and reaction conditions, but some generalizations are possible. Under basic conditions, the active iodinating species are iodine(III) compounds in which any relatively acidic ligands on iodine (such as acetate) have been replaced by alkoxide. [1]
A carbon–lead bond. Organolead chemistry is the scientific study of the synthesis and properties of organolead compounds, which are organometallic compounds containing a chemical bond between carbon and lead. The first organolead compound was hexaethyldilead (Pb 2 (C 2 H 5) 6), first synthesized in 1858. [1]
In extreme cases the periodate may be exchanged for lead tetraacetate which reacts in a similar manner and is soluble in organic solvents (Criegee oxidation). Periodate cleavage is often utilized in molecular biochemistry for the purposes of modifying saccharide rings, as many five- and six-membered sugars have vicinal diols. Historically it ...