Tetraphenylethylene oxide

Perhaps the earliest recorded illustration of the use of hydrogen iodide ia the reaction of tetraphenylethylene oxide (Eq. 404), which yields 1,1,2,2-tetraphenylethane in the presence of phosphorus.171 ... 

Under tho influence of various catalysts triphenykthylew oxide - and tetraphenylethylene oxide 7 have been ic)>ovU-phenyl migration over hydride migration with this particular substitution pattern. 

Thomer and Zinche1714 1710 utilized hot chromic acid to carry out oxidative de v ge of tetraphenylethylene oxide and related subetanees (Eq. 426). In a similar manner R be and Hallensieben1484 oxidized atilbcne oxide to benzoic add with chromic add (Eq. 429). 

CrO -AciO-AcOH. This reagent, diacetyl chromate, oxidizes tetraphenyl-ethylene largely to benzopinacol carbonate and tetraphenylethylene oxide, with a minor amount of benzophenone. ... 

Tetraphenylethylene oxide—no reaction 1,1-Diphenylethylene oxide—no reaction Burgstahler prepared the reagent by stirring lithium shot in ethylamine until the blue color was completely discharged and used it for isomerization of the non-conjugated diene (1) to (2). Mineral acids failed to effect isomerization. Lithium di-... 

Benzpinacolin sym, Tetraphenylethylene oxide, bsmopmacoline, triphenyU)enzoylmetkane)... 

Thermolysis of the 2,3-dispirocyclopropyl sulphite (182) afforded, in e-sumably via dicyclopropylidene oxide, the cyclobutantme (183). Benz-pinacol sulphite gave tetraphenylethylene oxide in virtually quantitative... 

Anodic oxidation of tetraphenylethylene at a platinum electrode leads to the product of cycliza-tion, namely, 9,10-diphenylphenanthrene (Stuart and Ohnesorge 1971). 

Mosher and co-workers1 44 have, on the oilier hand, recently published the first known instance of epoxidation with potassium T rmanganate, whereby tetraphenylethylene is converted into tetra-plu-nyLetliylcne oxide (Eq, 125). 

Anodic oxidation of tetraphenylethylene at a platinum electrode leads to the product of cyclization, namely, to 9,10-diphenylphenanthrene (Stuart Ohnesorge 1971). The intramolecular coupling reaction does not occur when diphenylethylenes, i.e., stilbene and its methyl derivatives, are electrolyzed under the same conditions (Stuart Ohnesorge 1971). This difference in the anodic behavior of these substances was attributed to the low stability of the cation radicals of stilbene and its methyl derivatives in comparison to the cation radicals of tetraphenylethylene. The participation of the cation radicals in cyclization of tetraphenylethylene has been unequivocally proved (Svanholm et al. 1974 Steckhan 1977). 

Tetraphenylethylene cyclizes anodically to 9,10-diphenylphenanthrene analogously to its photooxidative cyclization. The attempted anodic cyclization of cis- or frans-stilbene to phenanthrene however failed due to electrophilic reaction of the intermediate radical cation with the solvent 37S Primary aromatic amines are oxidized to radical cations which, depending on the pH of the electrolyte couple to aminodiphenylamines (C-N coupling (84) in Eq. (172) ), yield benzidines (85) at low pH (C-C coupling) or dimerize to hydrazobenzene (86) (N-N coupling) which is subsequently oxidized to azobenzene (Eq. (172) ) 2 5,376,377)... 

Diphenyldiazomethane is reversibly oxidized at a platinum electrode to a dia-zonium radical cation 93 (Eq. (181) ) that reacts with excess diphenyldiazomethane 94 in a radical chain process to form tetraphenylethylene (95) as the main product and benzophenone (96) and benzpinacolin (97) as side products resulting from chain termination 387). 

Tetrachloro-l, 3-dithietane forms a bis adduct with mercury (I) nitrate,whose structure was investigated by IR and Raman spectra. A cyclo-pentadienyl manganese(0) dicarbonyl complex of the dimer of 2,3-diphenylcyclo propenethione has been reported. Raney nickel desulfurizes the tetraester 538 and the desulfurization of the questionable dithietanes obtained by dimerization of thiofluorenone and thiobenzophenone give, respectively, bis-fluorenylidene and tetraphenylethylene. The electrochemical oxidation of 1,3-dithietane has been investigated. 2,2 -[Oxybis(methylene)]bis-l,3-dithietane is inert to boron trifluoride etherate after 30 days at room temperature. ... 

Oxidation of tetraphenylethylene (TPE) in CF3COOH or CH2CI2-CF3COOH [20,23] gives a radical cations table on the CV time scale, but that undergoes second-order decomposition according to this rate law rate = ] /[TPE], The product... 

The oxidation of substituted tetraphenylethylenes (IV) to dications depends on the solvent and substituents, and is either separated and sequential (two one-electron waves observed, E > E ), concerted (single two-electron wave, E < E ) or sequential with AE = 0. 

Chromyl chloride oxidation of tetraphenylethylene (4) results in cyclization to give 9,10-diphenylphenanthrenc (5) in 70% yield.9 The major product of the oxidation of 1,1,2,2-tetraphenylethanol by chromyl chloride is also (5). °... 

The hydrocarbon is a stable compound which melts at 211°. It is oxidized by chromic acid to benzophenone (Cells)2CO. When passed through a red-hot tube the hydrocarbon loses hydrogen, and an unsaturated compound, tetraphenylethylene, (C6Hs)2C =C(CeH5)2, is formed. Other hydrocarbons undergo a similar decomposition. 

Stilbene is an unusual arene as a ligand in that it offers the possibility of coordination to an arene ring or to the double bond. In spite of the abundance of rare earth naphthalene complexes in hterature (Bochkarev, 2002 Bochkarev et al., 1997 Fryzuk et al., 2000), ( )-stilbene complexes are rare. Evans et al. reported the synthesis of [(C5Me5)2Sm]2((E)-stilbene) from the direct reaction of (C5Me5)2Sm and ( )-stUbene (Chart 23 Evans et al., 1990). Due to the poor quality of the crystal, the structure of the molecule could not be unambiguously determined but the authors suggested an unsym-metrical coordination mode based on coimectivity. The analogous samarium styrene and butadiene complexes (styrene complex shown in Chart 23) showed two-electron reduction of the C=C bond and concomitant oxidation of Sm(ll) to Sm(lll) (Evans et al., 2001). Related yttrium and lutetium complexes of the readily available tetraphenylethylene dianion have been reported with similar stmctural features (Chart 23 Roitershtein et al., 1998, 2004). 

It is evident now, therefore, that fluoride ion is indeed a poor nucleophile but reaction does occur to a small extent. Some cation radicals are inert even in anodic fluorination reactions, e.g., that of tetraphenylethylene (42). However, why many other anodic fluorinations are successful and "chemical" reactions are not is yet to be answered. Possibly, the answer lies in the second oxidation step (eq. 43) which may be easy at an anode but difficult by, say, ArH " " in "chemical reactions. 

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