Ethers ozone adducts

Anthryl ethers afford protection to alcohol functions treatment of the derivative with singlet oxygen, generated via the triphenyl phosphite-ozone adduct, followed by mild catalytic reduction, effects regeneration of the free alcohol (Scheme 136). 

The synthesis of fullerene epoxides via [2 -I- l]-photoq cloaddition of singlet oxygen has already been discussed (in the section [2 -1- l]-Photocycloaddition ). Alternatively, fullerene oxides can also be obtained by thermolysis or photolysis of the [6,6]-closed ozone adduct of Qq and C70, namely 60 3 75 and C70O3 77.Thermolysis of QqOj yields the fullerene epoxide with a [6,6]-closed structure. In contrast, photolysis resulted in the formation of the [5,6]-open oxidoannulene 76 with an ether structure (Scheme 32). 

Titanium oxide dichloride [13780-39-8] TiOCl2, is a yellow hygroscopic soHd that may be prepared by bubbling ozone or chlorine monoxide through titanium tetrachloride. It is insoluble in nonpolar solvents but forms a large number of adducts with oxygen donors, eg, ether. It decomposes to titanium tetrachloride and titanium dioxide at temperatures of ca 180°C (136). 

The reagent was used to obtain (R)-( + )-frontalin (5) from the aldehyde 2, available in two steps from (3R)-( —)-linalool. The adduct 3 from reaction of 2 with 1 was converted to the diol 4 by ozonation and reduction. Treatment of 4 with BF, etherate effects conversion to the methyl ketone and then cycli/ation to 5. 

When the solvent is or contains an alcohol, it is often incorporated in the ozonation products For example, Kratzl et al (1976) obtained about one mole of ethyl formate per mole of veratrole ozonized when the solvent was 10% ethanol in chloroform Tanahashi et al (1975) obtained methyl esters and, on hydrogenolysis of some ozomde/methanol adducts, methyl benzyl ethers using... 

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