Sultones photolysis

The pyrolysis of (5-sultones with two double bonds forms a general synthetic route to substituted furans (equation 73)". De Mayo and his coworkers have shown that photolysis of unsaturated sultones in the presence of nucleophiles100101 produces the corresponding ketosulphonic acid derivatives (equation 74). A general mechanism was... 

A new carbon-carbon bond is formed when the sultone (180) is irradiated initially a ring-opened sulphonate ester is produced, and in a second photochemical stage ring-closure occurs after a-cleavage of the sulphonate. Carbon-carbon bond formation to an aromatic system is also apparent in the formation of the major product in the photolysis of (181) in the presence of diphenylacety lene. ... 

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