Triphenylphosphite ozonate

Oxidation of tUkyiidenetriphenylphosphoranes. Ylides of type (1) are oxidized by the triphenylphosphite-ozone adduct to alkenes (2) ylides of type (3) are... 

The synthesis of 3 may be simplified further by linking the C20- units 59 or 60 oxidatively or reductively, respectively. Thus reduction of 60 with low-valency titanium compounds [64] or oxidation of 59 with triphenylphosphite-ozone adduct [65] afford 3 in yields of 85% and 75%, respectively. In a process developed at BASF the phosphonium salt 59 is reacted with hydrogen peroxide in aqueous alkaline solution [62]. After separation of triphenylphosphine oxide and thermal isomerization, (all- )-3 conforming to type specifications is obtained in yields of approximately 70% based on vitamin A acetate (26) (Scheme 17). 

The expected initial reaction between ozone and amines would be an electrophilic ozone attack to give adduct I (Reaction 1) ), A similar adduct has actually been observed in the reaction between the nucleophile triphenylphosphite and ozone (20). It occurred to us that all of the reactions described above could be explained by competing fates... 

Triphenylphosphite forms an ozone adduct at low temperature, which decomposes on warming to triphenylphosphate and singlet oxygen ... 

Some polymers can also react with singlet oxygen ( O2), which can be generated in the polluted atmosphere [1789, 1810], and under laboratory conditions including physical (microwave discharge) and chemical (thermal decomposition of ozone-triphenylphosphite adduct) and many other methods. 

---