14987-65-6

Upstream product

• 4705-34-4 1,2-bis(4-methoxyphenyl)ethene 
• 2510-75-0 cis-4,4'-dimethoxystilbene 
• 1217-45-4 9,10-Dicyanoanthracene 
• 14987-65-6 trans-2,3-Bis(4-methoxyphenyl)oxirane 

Downstream Products

• 1217-45-4 9,10-dicyanoanthracene radical anion 
• 14987-65-6 trans-2,3-bis(4-methoxyphenyl)oxirane radical cation 
• 110003-04-8 cis-3,5-bis(4-methoxyphenyl)-1,2,4-trioxolane 
• 107245-97-6 (2S,5R)-2,5-Bis-(4-methoxy-phenyl)-furan-3,3,4,4-tetracarbonitrile 
• 107245-98-7 (2R,5R)-2,5-Bis-(4-methoxy-phenyl)-furan-3,3,4,4-tetracarbonitrile 
• 90522-26-2 Dimethyl 2,5-Bis(4-methoxyphenyl)-2,5-dihydrofuran-3,4-dicarboxylate 
• 84702-71-6 3,5-bis(4-methoxyphenyl)trioxolane 
• 90522-28-4 Dimethyl 2,5-Bis(4-methoxyphenyl)furan-3,4-dicarboxylate 

Relevant academic research and scientific papers

Experimental evidence for multiple oxidation pathways in the (salen)Mn-catalyzed epoxidation of alkenes

The substrate electronic effects on the selectivity in the catalytic epoxidation of para-substituted cis stilbenes 2a-i were investigated by using (R,R)-[N,N′-bis(3,5-di-tBu-salicylidene)-1,2-cyclohexanediamine] manganese(III) chloride 1 in benzene as the catalyst with iodosobenzene as the terminal oxidant. A Hammett study of the selectivity results reveals a stronger electrophilic character than previously assumed in the (salen)Mn-catalyzed reaction. In general, the best correlations with the experimental values were obtained by using the Hammett σ+ values, which gave ρ = -1.37 for the rate of cisepoxide formation and ρ = -0.43 for the rate of the stepwise process leading to the corresponding trans product. The reaction involves two separate pathways as indicated also by the competitive breakdown of the intermediate on the path to trans epoxide for methoxy-substituted substrates. The asynchronicity in the concerted pathway leading to cis epoxide is apparent for 4-methoxy-4′-nitrostilbene, which yields cis epoxide with 75% ee entirely as a result of electronic effects.

Mechanism of manganese porphyrin-catalyzed oxidation of alkenes. Role of manganese(IV)-oxo species

The mechanism for the bimolecular reaction of meso-tetrakis(2,6-dichlorophenyl)porphinato-oxo-manganese-(IV), [(C18TPP)MnIV(O)], with alkenes has been investigated by kinetics and product identification. Kinetic studies were carried out with 11 alkenes (trear-4-methoxystilbene, cis-4-methoxystilbene, 1,4-diphenyl-1,3-butadiene, 4-methoxystyrene, 1,1-diphenylethylene, 4-methylstyrene, 2,3-dimethyl-2-butene, trans-stilbene, cis-stilbene, styrene, 4-acetoxystyrene) in methylene chloride solution (30 °C) in air. The reactivities of the alkenes show that the trans alkenes are slightly more reactive than their cis isomers and that electron releasing substituents slightly favor the reaction. The second-order rate constant values (k2) correlate well with the potentials for the le- oxidation (E1/2) of the alkenes. The slope of the linear plot of log k2 vs E1/2for the series of alkenes (slope = -0.89 V-1) indicate that a mechanism of epoxidation involving rate-determining formation of an alkene derived π-cation-radical is unlikely. For the reaction with substituted styrenes, the linear free-energy relationship of log k2 vs σ (p+ = -0.99) supports a transition state with very little charge separation. Product yields determined for the reactions with cis-stilbene, transstilbene, 2,3-dimethyl-2-butene, cis-4-methoxystilbene, and trans-4-methoxystilbene are in accord with a mechanism involving the formation of a (porph)MnIIIOCC? radical intermediate. Thus, the products of cis-stilbene oxidation under aerobic conditions are cis-stilbene oxide (7%), frans-stilbene oxide (5%), and benzaldehyde (3%). Comparison with the reactions carried out under conditions favoring the transiently stable manganese(V)-oxo species showed more efficient epoxidation with a greater degree of stereospecificity. In a search for radical intermediates the cis olefinic substrate (Z)-1,2-bis(trans-2,trans-3-diphenylcyclopropyl)ethene was used as a radical trap. While no epoxide products were found, a polar oxygen-containing product resulting from the opening of one trans-2,trans-3-diphenylcyclopropyl ring by a cyclopropylcarbinyl to homoallylcarbinyl radical rearrangement (CPCRR) was detected supporting the formation of a neutral carbon radical species.

Synthetic Studies on O-Heterocycles via Cycloadditions. Part 1. Photochemical (Electron Transfer Sensitised) C-C Cleavage of Diaryloxiranes

Irradiation of trans-stilbene oxide with naphthalene-1,4-dicarbonitrile as sensitiser in the presence of electron deficient dipolarophiles leads, via a presumed carbonyl ylide, to various dihydro- and tetrahydro-furans.This chemistry is extended, for the

Photoinduced Electron Transfer Reaction. Part 3. 9,10-Dicyanoanthracene-sensitized Photo-oxidation of Electron-rich Stilbene Oxides

The 9,10-dicyanoanthracene (DCA)-sentisized photo-oxygenation of the electron-rich stilbene oxides (1) gives the ozonides (2) almost quantitatively.The fluorescence of DCA is quenched by (1) at a diffusion-controlled rate and the above reaction is quenched by polymethoxybenzenes which indicates that an electron transfer mechanism is involved.The quantum yield for ozonide formation varies from 0.6 for trans-2-(4-methoxyphenyl)-3-phenyloxirane (1d) to 2.4 for trans-2,3-bis(4-methoxyphenyl)-2,3-diethyloxirane (1h), suggesting a duplex reaction mechanism such as photo-oxygenation by superoxide and a Barton mechanism after the initial electron transfer from the epoxides (1) to the excited singlet state of DCA.

Oxidation of Alkenes and Sulphoxides with a Mixture of Potassium Superoxide and Diethyl Chlorophosphate

The reaction of potassium superoxide with diethyl chlorophosphate in the presence of 18-crown-6 ether gave at least two oxidizing agents, one of which was electrophilic and used in the oxidation of alkenes, whilst the other, nucleophilic in type, was important in the oxidation of sulphoxides.