Comparison of the photooxidations of 1,5-dithiacyclooctane, 1,4-dithiane, and pentamethylene sulfide. Another example of remote participation during photooxidation at sulfur ?

The photooxidations of 1,5-dithiacyclooctane (1,5-DTCO), 1,4-dithiane, and pentamethylene sulfide have been compared. The photooxidation of 1,5-DTCO differs significantly from the other substrates in several respects: (1) the ratio of chemical quenching to total quenching of singlet oxygen during photooxidation of 1,5-DTCO is 70%, in comparison to 5% for 1,4-dithiane and 2.9% for pentamethylene sulfide; (2) a sulfone is produced in all of the photooxidations except in that of 1,5-DTCO; and (3) the value of k T is larger for 1,5-DTCO than for any previously reported sulfide