Oxidative functionalization of olefins

The observation that the previously described diacetoxylation of olefins by means of tel-lurinic anhydrides produces quantitative yields of the corresponding ditellurides suggested the oxidative functionalization of olefins employing diphenyl diteUuride combined with an oxidizing agent instead of the tellurinic anhydride. ... 

Abstract The oxidative functionalization of olefins is an important reaction for organic synthesis as well as for the industrial production of bulk chemicals. Various processes have been explored, among them also metal-catalyzed methods using strong oxidants like osmium tetroxide. Especially, the asymmetric dihydroxylation of olefins by osmium(Vlll) complexes has proven to be a valuable reaction for the synthetic chemist. A large number of experimental studies had been conducted, but the mechanisms of the various osmium-catalyzed reactions remained a controversial issue. This changed when density functional theory calculations became available and computational studies helped to unravel the open mechanistic questions. This mini review will focus on recent mechanistic studies on osmium-mediated oxidation reactions of alkenes. 

The oxidative functionalization of olefins mediated by transition metal oxides leads to a variety of products including epoxides, 1,2-diols, 1,2-aminoalcohols, and 1,2-diamines [1]. Also the formation of tetrahydrofurans (THF) from 1,5-dienes has been observed, and enantioselective versions of the different reactions have been developed. Although a lot of experimental data has been available, the reaction mechanisms have been a subject of controversial discussion. Especially, osmium (VIII) complexes play an important role there, as the proposal of a stepwise mechanism [2] for the dihydroxylation (DH) of olefins by osmium tetroxide (OSO4) had started an intense discussion about the mechanism [2—11],... 

The oxidative functionalization of olefins through ir-olefin complexes of palladium also has a long history, including the industrial production of acetaldehyde and vinyl acetate. Related reactions, including the conversion of olefins to vinyl ethers and enamines, have been studied in more recent times for fine chemical synthesis. These oxidative C-0 and C-N bond formations have been conducted with a variety of oxidants, including Oj, and have been studied as both intermolecular and intramolecular processes. 

The oxidative functionalization of olefins to generate aldehydes, ketones, vinyl ethers, vinyl acetates, allylic acetates, and allylic ethers, as well as enamides, allylic amines, and products containing new C-C bonds has been studied extensively in both industrial and academic... 

Wacker-type oxidations have not only been used to prepare commodity chemicals, but have been used in complex molecule synthesis. Examples of the use of three classes of the oxidative functionalizations of olefins in natural products synthesis are shown in Schemes 16.27-16.30. 

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