Catalytic oxidation of alkenes

This subject has recently been reviewed.647 Several additional papers have appeared on the catalytic oxidation of alkenes by 02 in the presence of PdCl(MeCN)2N02(148).64S Terminal alkenes and trans- cyclooctene yield the corresponding ketones, cyclopentene and cyclohexene the corresponding allyl alcohol, and bicyclic alkenes the corresponding epoxide. Heterometallacy-clopentanes such as (152) have been isolated from the reaction of (148) with norbornene (dicy-clopentadiene), and characterized by X-ray crystallography.6486 Glycol monoacetates were obtained from the reaction of (148) with terminal alkenes in acetic acid.649... 

Stoichiometric and catalytic transition-metal oxidation reactions are of great interest, because of their important role in industrial and synthetic processes. The oxidation of alkenes is one of the fundamental reactions in chemistry.1 Most bulk organic products contain functional groups, which are produced in the chemical industry by direct oxidation of the hydrocarbon feedstock. Usually these reactions employ catalysts to improve the yields, to reduce the necessary activation energy and render the reaction more economic. The synthesis of almost every product in chemical industry nowadays employs at least one catalytic step. The oxidation products of alkenes, epoxides and glycols, may be transformed into a variety of functional groups and therefore the selective and catalytic oxidation of alkenes is an industrially important process. 

It was postulated that one possible intermediate for metalloporphyrin-promoted epoxidation is intermediate 41 (Scheme 3.7) [126], If it were possible to trap intermediate 41 with external nucleophiles such as water, a new type of catalytic oxidation of alkenes could be performed. 

Preparation.—Catalytic Oxidation of Alkenes to Oxirans, using Oxygen or Oxygen-containing Gases. The mechanism for the conversion of the phenol (1) into the epoxy-quinol (4) by molecular oxygen in Bu OK-Bu OH has been investigated (Scheme 1)." The first step is the formation of hydroperoxide (2), which is converted into hydroperoxide (3) via a -n--complex intermediate the yield of (4) increases with temperature. 

Geier, G.R., III Sasaki, T. Catalytic oxidation of alkenes with a surface-bound metalloporphyrin-peptide conjugate. Tetrahedron 1999, 55 (7), 1859-1870. 

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