Phenylseleninic acid

This reaction depends upon the facile solvolysis of (J-haloselenides and the facile oxidative elimination of a selenoxide, which was discussed in Section 6.6.3. An alternative method, which is experimentally simpler, involves reaction of alkenes with a mixture of diphenyl diselenide and phenylseleninic acid.189 The two selenium reagents generate an electrophilic selenium species, phenylselenenic acid, PhSeOH. 

SCHEME 117. Alcohol oxidation under biphasic conditions using immobilized phenylseleninic acid/ TBHP as catalyst... 

SCHEME 161. Baeyer-ViUiger oxidation using polymer-bound phenylseleninic acid and H2O2... 

K0.S02.SeRN02 + 2HaO +12 = (RN02)2Se2 + 2KHS04 + 2HI Phenylseleninic acid,1... 

Polystyrene-bound phenylseleninic acid has been used in catalytic amounts in a trii asic system consisting of the polymer, aqueous hydrogen peroxide, and dichloromethane, to catalyze the oxidation of al-... 

A solution of 0.82 g (10 mmol) of cyclohexene and 1.9 g (10 mmol) of phenylseleninic acid in 10 mL of HOAc is heated at 80 °C for 24 h with stirring. After completion of the reaction, evaporation of HOAc gives a dark orange oil, which is purified by distillation to give lrans-33-, yield 2.41 g (81 %) bp 137-138 °C/ l Torr. 

As an electrochemical reaction, Torii and co-workers demonstrated that the facile transformation of alkenes into allylic alcohols and ethers proceeded in the presence of a catalytic amount (10 mol%) of diphenyl diselenide (Scheme 15) [18]. Most of terminal co double bonds of isoprenoids undergo regioselective oxyselenenylation-deselenenylation to give frans-allylic alcohols in aqueous acetonitrile and methyl ethers in methanol. The addition of SOI salts improves chemical yields since SOI salts prevent the conversion of phenylselenenic acid (PhSeOH) into the inert phenylseleninic acid (PhSe02H) by both disproportionation and electro-oxidation. This method was also applied to intramolecular reaction to form -lactone in high yield. 

Peroxyseleninic acids. Treatment of a mercurated 2%-crosslinked polystyrene with selenium dioxide affords a yellow polymer (Equation 6) which has been assigned the structure of polymer-bound phenylseleninic acid (32). 

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