Photochemical reduction of .beta.- and .gamma.-oxo sulfones

Photochemistry of thioxanthen-9-one-10,10-dioxide: A remarkably reactive triplet excited state

“…Based on its spectroscopic data, this species was assigned to the corresponding pinacol 2 formed through an initial hydrogen abstraction of triplet 1 from the solvent (Scheme 1). This is fully in accord with a literature report of pinacol formation upon steady-state photolysis of thiochroman-4-one 1,l-dioxide and isothiochroman-4-one 2,2-dioxide in the presence of hydrogen donor solvents [38].…”

Photochemical rearrangements of substituted thiochromanone sulfoxides

“…The ultraviolet spectra of thiochroinanone sulfoxides (Table 1) show a marked similarity t o those of the analogous sulfones reported by us previously (11). However, in contrast to the sulfones, which are photochemically inert in solvents which are poor hydrogen-donors and give only moderate yields of pinacolic reduction products in alcoholic solvents, the foregoing discussion clearly reveals a very complex photochemistry for the keto-sulfoxides studied in this paper.…”

Chemo- and Diastereoselectivity in the Dimethyldioxirane Oxidation of 2,3-Dihydro-4H-1-benzothiopyran-4-ones and 4H-1-Benzothiopyran-4-ones. Unusual Reactivity of 4H-1-Benzothiopyran-4-one 1-Oxides1

“…The main advantage of our protocol is the mild conditions; the typical procedure − developed previously to synthesize 1-thiochroman-4-one 1,1-dioxides utilizes hot H 2 O 2 in acetic acid (in situ formation of peracid) as oxidant. Other oxidants such as monoperoxyphthalic acid (3−4 equiv), sodium perborate, and cold KMnO 4 in mixtures of acetic acid and water have been employed, limited to only one example.…”