Photoaddition of Water, Alcohols, and Carboxylic Acids

Numerous examples of the photoaddition of water, alcohols, and carboxylic acids to multiple carbon-carbon bonds have been reported. The photoaddition of water to pyrimidine derivatives is of probable biological significance (see Chapter 12)  

Alcohols add to olefins upon irradiation in two modes, to produce higher alcohols and to produce ethers. In most photochemical additions of alcohols the first mode occurs  

Irradiation of alcohols (ethanol, isopropanol, etc.) with maleic acid in the presence of benzophenone or anthraquinone as sensitizer leads to 1 1 addition products 

Similarly, isopropanol adds to cyclopentenone upon photolysis to yield ketoalcohol (38) 

This product probably arises from initial abstraction of a hydrogen radical from the isopropanol, followed by radical coupling  

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