Oxidation with chromium(VI) complexes: Difference between revisions

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'''Oxidation with chromium(VI)-amine complexes''' involves the conversion of alcohols to carbonyl compounds or more highly oxidized products through the action of molecular chromium(VI) oxide-amine adductsoxides and salts. The terminology is flawed because many of these complexes are not complexes with Cr-N bonds.<ref>Luzzio, F. A. ''[[Org. React.]]'' '''1998''', ''53'', 1. {{doi|10.1002/0471264180.or053.01}}</ref>

==Inventory of Cr(VI)-pyridine reagents==

One family of reagents employs the complex CrO₃(pyridine)₂.<ref>{{cite book |doi=10.1007/0-387-25725-X_1|chapter=Chromium-based Reagents|title=Oxidation of Alcohols to Aldehydes and Ketones|series=Basic Reactions in Organic Synthesis|year=2006|pages=1–95|isbn=0-387-23607-4}}</ref>

*Sarrett[[Sarett oxidation|Sarett's reagent]]: a solution of CrO₃(pyridine)₂ in pyridine. It was popularized for selective oxidation of primary and secondary alcohols to carbonyl compounds.

*[[Collins reagent]] is a solution of the same CrO₃(pyridine)₂ but in dichloromethane. The Ratcliffe variant of Collins reagent relates to details of the preparation of this solution, i.e., the addition of chromium trioxide to a solution of pyridine in methylene chloride.<ref name=JCC>{{cite journal | author = J. C. Collins, W.W. Hess | title = Aldehydes from Primary Alcohols by Oxidation with Chromium Trioxide: Heptanal | volume = 52 | pages = 5 | doi = 10.15227/orgsyn.052.0005 | year = 1972}}</ref>

The second family of reagents are ''salts'', featuring the pyridinium cation (C₅H₅NH⁺).