Strain-Assisted α-Cleavage Reactions of Thioketones: Cyclobutanethiones

Article abstract of DOI:10.1021/jo00172a008

Photochemical α-cleavage from the lowest triplet state (n?^*,T₁), resulting in the generation of a diradical intermediate, appears to be general for cyclobutanethiones.The diradical intermediate derived from 1,3-dithione is observed to undergo ring expansion to carbene or close to either dithione or dithiolactone.The photochemical behavior reported here for cyclobutanethiones is different from that of the corresponding cyclobutanones. α-Cleavage processes in the case of cyclobutanethiones are not efficient and are often accompanied by side reactions.