Unexpected solid-state photochemistry of an alpha-thiophenyl-alpha'-thiophenyl-S,S-dioxo-substituted ketone.
Samples of 2,4-dimethyl-2-(thiophen-3-yl)-4-(thiophen-3-yl-S,S-dioxo)pentan-3-one 2 were obtained by controlled MCPBA oxidation of 2,4-dimethyl-2,4-di(thiophen-3-yl)pentan-3-one 1. Rather than the expected photodecarbonylation, UV--vis irradiation of 2 led to the intramolecular 2 + 2 photocycloaddition product 5 in quantitative yields (by GC and NMR) both in solution and in crystalline solid state. Detailed X-ray powder diffraction analyses revealed that the solid-state reaction of sulfone 2 occurs with a loss of long-range order despite retaining some birefringence under polarized microscopy.
D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010422:Pentanones / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects*; D010777:Photochemistry; D033362:Powder Diffraction; D013696:Temperature; D013876:Thiophenes / Q000138:chemical synthesis* / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays
C527438:2,4-dimethyl-2,4-di(thiophen-3-yl)pentan-3-one; C527437:2,4-dimethyl-2-(thiophen-3-yl)-4-(thiophen-3-yl-S,S-dioxo)pentan-3-one; D010422:Pentanones; D013876:Thiophenes