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<span style="float:right;padding-right:50px;padding-top:30px;">'''''(1)'''''</span><center>[[File:ChroGen.png]]</center>
==Mechanism and
===Prevailing
Chromate esters have been implicated in most oxidations of alcohols by chromium(VI)-amines. After formation of the chromate ester, either deprotonation or hydride transfer leads to the product carbonyl compound. Kinetic isotope effect studies have shown that C-H bond cleavage is involved in the rate-determining step.<ref>Banerji, K. K. ''J. Org. Chem.'', '''1988''', ''53'', 2154.</ref>
<span style="float:right;padding-right:50px;padding-top:30px;">'''''(2)'''''</span><center>[[File:ChroMech1.png]]</center>
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<span style="float:right;padding-right:50px;padding-top:30px;">'''''(5)'''''</span><center>[[File:ChroMech3.png]]</center>
==Scope and
Buffering agents may be used to prevent acid-labile protecting groups from being removed during chromium(VI)-amine oxidations. However, buffers will also slow down oxidative cyclizations, leading to selective oxidation of alcohols over any other sort of oxidative transformation. Citronellol, for instance, which cyclizes to pugellols in the presence of PCC, does not undergo cyclization when buffers are used.<ref>Fieser, L. F.; Fieser, M. ''Reagents for Organic Synthesis''; Wiley-Interscience, New York, 1979, '''7''', 309.</ref><ref name=whatup>Babler, J. H.; Coghlan, M. J. ''Synth. Commun.'' '''1976''', ''6'', 469.</ref>
<span style="float:right;padding-right:50px;padding-top:30px;">'''''(6)'''''</span><center>[[File:ChroScope1.png]]</center>
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In addition to the limitations described above, chromium(VI) reagents are often unsuccessful in the oxidation of substrates containing heteroatoms (particularly nitrogen). Coordination of the heteroatoms to chromium (with displacements of the amine ligand originally attached to the metal) leads to deactivation and eventual decomposition of the oxidizing agent.
==Comparison with
Methods employing dimethyl sulfoxide (the [[Swern oxidation|Swern]] and [[Moffatt oxidation]]s) are superior to chromium(VI)-amines for oxidations of substrates with heteroatom functionality that may coordinate to chromium.<ref>Tidwell, T. ''Org. React.'' '''1990''', ''39'', 297.</ref> [[Dess-Martin periodinane]] (DMP) offers the advantages of operational simplicity, a lack of heavy metal byproducts, and selective oxidation of complex, late-stage synthetic intermediates.<ref>Dess, D. B.; Martin, J. C. ''J. Org. Chem.'', '''1983''', ''48'', 4156.</ref> Additionally, both DMP and [[manganese dioxide]] (MnO<sub>2</sub>) can be used to oxidize allylic alcohols to the corresponding enones without allylic transposition. When allylic transpositions is desired, however, chromium(VI)-amine reagents are unrivaled.
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