Styrene oxidative coupling

The oxidative coupling of alkenes which have two substituents at the 2 posi-tion, such as isobutylene, styrene, 2-phenylpropene, 1,1-diphenylethylene, and methyl methacrylate, takes place to give the 1,1,4.4-tetrasubstituted butadienes 285 by the action of Pd(OAc)2 or PdCF in the presence of sodium acetate[255-257]. Oxidation of styrene with Pd(OAc)2 produces 1.4-diphenylbutadiene (285, R = H) as a main product and a- and /3-acetoxystyrenes as minor pro-ducts[258]. Prolonged oxidation of the primary coupling product 285 (R = Me) of 2-phenylpropene with an excess of Pd(OAc)2 leads slowly to p-... 

A different approach, taken by both Monsanto (58) and Gulf Research and Development Company (59), involved the oxidative coupling of two molecules of toluene to yield stilbene. The stilbene is then subjected to a metathesis reaction with ethylene to yield two molecules of styrene. 

Another approach is the oxidative coupling of toluene to stilhene followed hy disproportionation to styrene and benzene ... 

Phenoxy acetophenone, 46, 94 Phenylacetyleue, oxidative coupling to diphenyldiacetylene, 46, 39 partial reduction to styrene using palladium catalyst, 46, 90 reaction with sodium hypobromite to yield phenylbromoethyne, 46,86... 

Rhodium complexes catalyze the oxidative coupling of benzene with ethene to produce styrene directly.45,45a,45b Using Rh(ppy)2(OAc) (ppyH = 2-phenylpyridine), the reaction of benzene with ethene in the presence of 02 and Cu(OAc)2 in benzene and acetic acid at 180 °C gives styrene and vinyl acetate in 77% and 23% selectivities, respectively. 

In most cases, the oxidative addition process consumes stoichiometric amount of Pd(OAc>2. One of the earliest examples of the use of palladium in pyrrole chemistry was the Pd(0Ac)2 induced oxidative coupling of A-methylpyrrole with styrene to afford a mixture of olefins 18 and 19 in low yield based on palladium acetate [28]. 

Table 21. Solvent dependence of coupling constants in styrene oxide, styrene sulfide and 2,2-dichlorocyclopropylbenzene...

Methane and Toluene to Styrene Basic catalysts in the presence of oxygen and/or air are reported to be attractive catalysts for this reaction. Most research was performed in the late 1980s and early 1990s. The fundamentals resemble the oxidative coupling reaction of methane to ethylene. 

Bis-oxazoline ligands can also be produced by oxidative coupling of the copper derivative of diastereoisomerically pure 306 (Scheme 145) . Further lithiations of the product 317, which was produced as single diastereoisomer, occur (as in Scheme 143) at the second site adjacent to the oxazoline, giving, for example, 318, despite the (presumably) less favourable stereochemistry of the lithiation step. Bisoxazolines 318 direct the asymmetric copper-catalysed cyclopropanation of styrene using diazoacetate. 

Oxidative coupling of specific alkenes such as styrene derivatives459 and vinyl acetate460 to 1,3-diene derivatives can also be achieved in the presence of palladium catalysts.367,455 This coupling essentially occurs head to head , i.e. the C—C bond formation involves the least substituted carbon atoms of the double bonds (equation 188).461... 

The alkene arylation reaction has been extensively studied by Moritani and coworkers462 and by Heck.463 An interesting application of this chemistry is the synthesis of styrene from the oxidative coupling of benzene and ethylene (equation 189).464... 

Chiral 1,3-diols. Coupling of diaryl ketones with chiral epoxides mediated by Yb (15, 366) provides chiral 1,3-diols in high optical yields. Generally two diols are formed by coupling at both carbon atoms, but coupling with styrene oxide occurs mainly at the more-substituted carbon. 

Adenosine-styrene oxide adducts, neutral and positively charged inosine-styrene oxide adducts, neutral and positively charged Hypersil ODS, 3 pm 30% Methanol, 10% acetonitrile in 5 mM aqueous ammonium acetate 250 mm x 25 pm i.d. CEC/MS (quadrupole) coupling... 

Siethoff et al. [73] reported the quantitative bioanalysis of nucleotides from DNA modified by styrene oxide by a combination of LC with ESI-MS and inductively coupled plasma mass spectrometry (ICP-MS). The LC-ICP-MS system was applied for phosphorous detection. This helped to evaluate response factors of various adducts in LC-ESI-MS, which were found to be almost identical. The... 

Examples Oxidative coupling of methane (OCM), oxidative dehydrogenation of C -C4 alkanes, partial oxidation of methane to synthesis gasa, combined oxidative coupling of methane and toluene to styrene Surface-stabilized combustion, partial oxidation of methane to synthesis gasa, synthesis of cyanic acid from methane, ammonia, and oxygen3... 

---