Alkenes selective oxidation

Since the rate of oxidation of terminal alkenes is much higher than that of internal alkenes, selective oxidation of terminal alkenic bonds is possible without attacking the internal alkenic bonds in various dienes (equation 7)... 

Atomically dispersed titanium in a mesoporous silica matrix have also been well documented as successful catalysts in alkene selective oxidation reactions using [116,123,124]. 

The reaction is carried out using a titanium silicalite-1 (TS-1) zeolite catalyst [30, 122]. This type of catalyst is known to accelerate the selective oxidation of alcohols, epoxidation of alkenes and hydroxylation of aromatics. These reactions have importance for fine-chemical production. 

The most widely used reagent for oxidation of alkenes to glycols is osmium tetroxide. Osmium tetroxide is a highly selective oxidant that gives glycols by a stereospecific syn addition.39 The reaction occurs through a cyclic osmate ester that is formed by a [3 + 2] cycloaddition.40... 

Trisubstituted alkenes are oxidized selectively at the more-substituted end of the carbon-carbon double bond, indicating that the ene reaction step is electrophilic in character. 

Diffusional constraints in selective oxidation of alkenes over Euro-TS-1 and Ti-Beta... 

He got a Habilitation a diriger les recherches in 2008 and he is now developing his own project that consists of the elaboration of new hybrid metalloprotein catalysts for selective oxidation reactions, by insertion of metal cofactors into xylanases. He then studies their peroxidase, catalase, and monooxygenase activities, in particular in the selective oxidation of sulfides, alkanes, and alkenes. 

Selective oxidation of sulfides, alkanes, and alkenes using iron biocatalysts and mimics. 

Alkanes, selective oxidation, cobalt catalysis, 44 291 Alkene... 

In 1989, a method for the peroxysilylation of alkenes nsing triethylsUane and oxygen was reported by Isayama and Mnkaiyama (eqnation 25). The reaction was catalyzed by several cobalt(II)-diketonato complexes. With the best catalyst Co(modp)2 [bis(l-morpholinocarbamoyl-4,4-dunethyl-l,3-pentanedionato)cobalt(n)] prodnct yields ranged between 75 and 99%. DiaUcyl peroxides can also be obtained starting from tertiary amines 87, amides 89 or lactams via selective oxidation in the a-position of the Af-fnnctional group with tert-butyl hydroperoxide in the presence of a ruthenium catalyst as presented by Murahashi and coworkers in 1988 ° (Scheme 38). With tertiary amines 87 as substrates the yields of the dialkyl peroxide products 88 ranged between 65 and 96%, while the amides 89 depicted in Scheme 38 are converted to the corresponding peroxides 90 in yields of 87% (R = Me) and 77% (R = Ph). 

As already mentioned above, sulfides are oxidized to the corresponding sulfoxides with alkyl hydroperoxides in the presence of various metal catalysts like Mo, W, Ti and V. In the presence of excess hydroperoxide further oxidation to the sulfone occurs. Sulfides are generally oxidized much faster than alkenes, which is reflected in the selective oxidation of unsaturated sulfides exclusively at the sulfur atom. During the last years many asymmetric versions of this reaction have been developed and can be mainly divided... 

Selective Oxidation of Alkanes, Alkenes, and Phenol with Aqueous H2O2 on Titanium Silicate Molecular Sieves... 

These multicomponent catalyst systems have been employed in a variety of aerobic oxidation reactions [27]. For example, use of the Co(salophen) cocatalyst, 1, enables selective allylic acetoxylation of cyclic alkenes (Eq. 6). Cyclo-hexadiene undergoes diacetoxylation under mild conditions with Co(TPP), 2 (Eq. 7), and terminal alkenes are oxidized to the corresponding methyl ketones with Fe(Pc), 3, as the cocatalyst (Eq. 8). 

Transition metals and their complexes can be immobilized in the mesopores or incorporated in the structure to make silica-supported metal catalysts. For instance, titanium catalysts for selective oxidation can be formed by modifying the mesoporous structure with either Ti grafted on the surface (Tif MCM-41) or Ti substituted into the framework (Ti->MCM-41). The grafted version makes the better catalyst for the epoxidation of alkenes using peroxides, and has good resistance to leaching of the metal. 

The oxidation of simple internal alkenes is very slow. The clean selective oxidation of a terminal double bond in 40, even in the presence of an internal double bond, is possible under normal conditions[89,90]. The oxidation of cyclic alkenes is difficult, but can be carried out under selected conditions. Addition of strong mineral acids such as HC104, H2S04 and HBF4 accelerates the oxidation of cyclohexene and cyclopentene[48,91). A catalyst system of PdS04-H3PMo6W604o [92] or PdCT-CuCh in EtOH is used for the oxidation of cyclopentene and cyclohexene[93]. 

The selective oxidation of terminal alkenes to the corresponding methyl ketones was reported by Roussel and Mimoun in 1980 and can be carried out using t-butylperoxypalladium(II) trifluoroacetate (PPT) or alternatively catalytic amounts of... 

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