Olefin oxidation carbonyl compounds

Ethylene oxide reacts with phosphonium haUdes to give yUdes, which are used to synthesize olefins from carbonyl compounds, such as aldehydes and ketones (92). 

The oxidation of olefins to carbonyl compounds by palladium (II) ion can be regarded as an addition of a palladium hydroxide group to the olefin followed by a hydrogen shift. Kinetic evidence suggests the following mechanism for the oxidation of ethylene by palladium chloride in aqueous solution containing excess chloride ion 21, 49, 99). 

Interesting properties may also be obtained when using a mixed addenda system in the presence of a co-catalyst The best known system [34d] is the V-substituted phosphomolybdate in conjunction with Pd for the oxidation of olefins to carbonyl compounds. This is analogous to the Wacker oxidation process based on CUCI2 and Pd. Unlike the Wacker process, the HPA system works at very low chloride concentration, or even in its absence. In addition the HPA is more active and selective and less corrosive. Other examples of such two-component catalytic systems include TF /TP, PT /Pt ", Ru"7Ru ", Br 7Br" and l /h-... 

The oxidation of olefins to carbonyl compounds by means of palladium chloride catalysts (and involving intermediate organopalladium compounds) 22, 225, 226),... 

An interesting variation on the oxidation of olefins to carbonyl compounds has been described by Rodeheaver and Hunt (227). These workers prepared the hydroxy mercurials and exchanged these mercurials with PdCla to give the hydroxypalladation adduct which then decomposed in the expected fashion to give ketones ... 

Aqueous PdCb oxidizes olefins to carbonyl compounds—e.g., ethylene gives acetaldehyde (Reaction 1). 

Oxidation of Olefins to Carbonyl Compounds (Wacker Process)... 

Yates, M. H. One-pot conversion of olefins to carbonyl compounds by hydroboration/NMO-TPAP oxidation. Tetrahedron Lett. 1997, 38, 2813-2816. 

Tyriik, S., Wolochowicz, I. Application of transition metal complexes with low oxidation states in organic synthesis. I. New synthesis of olefins from carbonyl compounds. Bull. Soc. Chim. Fr. 1973, 2147-2148. 

Jira, R. Oxidation of olefins to carbonyl compounds (Wacker process). Applied Homogeneous Catalysis with Organometallic Compounds 1996, 1, 374-393. 

R. lira, Oxidation of Olefins to Carbonyl Compounds (Wacker Process) , in Applied Homogeneous Catalysis with Ogranometallic Compounds, B. Comils, W. A. Herrmann, Eds., pp. 374—393, VCH, Weinheim, Germany, 1996. 

R] Jira, R. Oxidations Oxidation of olefins to carbonyl compounds (Wacker process). In Applied Homogeneous Catalysis with Organometallic Compounds (2nd Edition) Comils, B. Herrmann, W. A. (Eds.), Wiley-VCH Weinheim, Germany, 2002, /, pp386-405. 

Manganese(III) can oxidize carbonyl compounds and nitroalkanes to carboxy-methyl and nitromethyl radicals [186]. With Mn(III) as mediator, a tandem reaction consisting of an intermolecular radical addition followed by an intramolecular electrophilic aromatic substitution can be accomplished [186, 187). Further Mn(III)-mediated anodic additions of 1,3-dicarbonyl and l-keto-3-nitroalkyl compounds to alkenes and alkynes are reported in [110, 111, 188). Sorbic acid precursors have been obtained in larger scale and high current efficiency by a Mn(III)-mediated oxidation of acetic acid acetic anhydride in the presence of butadiene [189]. Also the nitromethylation of benzene can be performed in 78% yield with Mn(III) as electrocatalyst [190]. A N03 radical, generated by oxidation of a nitrate anion, can induce the 1,4-addition of aldehydes to activated olefins. NOj abstracts a hydrogen from the aldehyde to form an acyl radical, which undergoes addition to the olefin to afford a 1,4-diketone in 34-58% yield [191]. 

The palladium chloride-coppeifll) chloride couple (28, 29) used industrially in the Wacker process oxidizes olefins to carbonyl compounds. Experimental kinetic and isotope effect data (30) seem to indicate that a TT-olefin complex is initially formed in a series of preequilibrium steps. The rate-determining step is postulated to be a rearrangement of the TT-olefin complex to a cr-complex followed by the final breakdown of the cr-complex to products. Figure 13 depicts the widely accepted Henry mechanism (31). 

The oxidation of olefins to carbonyl compounds in the presence of PdCl2 and CUCI2, which represents the catalysts of the commercial acetaldehyde process, is accompanied by chlorinating reactions. These side reactions can reduce the yield of the desired products considerably. Different ways have been suggested to reoxidize Pd°, avoiding the chlorinating behavior of CUCI2. 

The nucleophilic addition to polyene (e.g., alkene, diene, arene) and polyenyl (e.g., allyl, cyclopentadienyl) ligands has contributed significantly to the numerous and unique applications organometallic reagents have in organic synthesis. The catalytic oxidation of olefins to carbonyl compounds (e.g., the palladium-mediated conversion... 

Trialkylamines in aqueous solution undergo hydroxide ion catalyzed oxidative dealkylation, affording secondary nitroxyl radicals R R N-O beside olefins and carbonyl compounds [57]. An... 

Oxovanadium(V)-Induced Oxidative Transformations of Olefinic and Carbonyl Compounds... 

Olefin synthesis starts usually from carbonyl compounds and carbanions with relatively electropositive, redox-active substituents mostly containing phosphorus, sulfur, or silicon. The carbanions add to the carbonyl group and the oxy anion attacks the oxidizable atom Y in-tramolecularly. The oxide Y—O" is then eliminated and a new C—C bond is formed. Such reactions take place because the formation of a Y—0 bond is thermodynamically favored and because Y is able to expand its coordination sphere and to raise its oxidation number. 

The highly ionic thaHic nitrate, which is soluble in alcohols, ethers, and carboxyhc acids, is also a very useful synthetic reagent. Oxidation of olefins, a,P-unsaturated carbonyl compounds, P-carbonyl sulfides, and a-nitrato ketones can aH be conveniently carried out in good yields (31,34—36). 

Polymerization of olefins such as styrene is promoted by acid or base or sodium catalysts, and polyethylene is made with homogeneous peroxides. Condensation polymerization is catalyzed by acid-type catalysts such as metal oxides and sulfonic acids. Addition polymerization is used mainly for olefins, diolefins, and some carbonyl compounds. For these processes, initiators are coordination compounds such as Ziegler-type catalysts, of which halides of transition metals Ti, V, Mo, and W are important examples. 

Since double bonds may be considered as masked carbonyl, carboxyl or hydroxymethylene groups, depending on whether oxidative or reductive methods are applied after cleavage of the double bond, the addition products from (E)-2 and carbonyl compounds can be further transformed into a variety of chiral compounds. Thus, performing a second bromine/lithium exchange on compound 4, and subsequent protonation, afforded the olefin 5. Ozonolysis followed by reduction with lithium aluminum hydride gave (S)-l-phenyl-l,2-ethanediol in >98% ee. 

NMR spectroscopic studies f111,13C, and 31P) are consistent with the dipolar ylide structure and suggest only a minor contribution from the ylene structure.234 Theoretical calculations support this view.235 The phosphonium ylides react with carbonyl compounds to give olefins and the phosphine oxide. 

For internal olefins, the Wacker oxidation is sometimes surprisingly regioselective. By using aqueous dioxane or THF, oxidation of P,y-unsaturated esters can be achieved selectively to generate y-keto-esters (Eq. 3.18).86 Under appropriate conditions, Wacker oxidation can be used very efficiently in transforming an olefin to a carbonyl compound. Thus, olefins become masked ketones. An example is its application in the synthesis of (+)-19-nortestosterone (3.11) carried out by Tsuji (Scheme 3.5).87... 

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