Unexpected solid-state photochemistry of an alpha-thiophenyl-alpha'-thiophenyl-S,S-dioxo-substituted ketone

J Org Chem. 2008 Jan 18;73(2):638-43. doi: 10.1021/jo702127g. Epub 2007 Dec 23.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclization
  • Models, Molecular
  • Molecular Structure
  • Oxidation-Reduction
  • Pentanones / chemical synthesis*
  • Pentanones / chemistry
  • Pentanones / radiation effects*
  • Photochemistry
  • Powder Diffraction
  • Temperature
  • Thiophenes / chemical synthesis*
  • Thiophenes / chemistry*
  • Thiophenes / radiation effects
  • Ultraviolet Rays*

Substances

  • 2,4-dimethyl-2,4-di(thiophen-3-yl)pentan-3-one
  • 2,4-dimethyl-2-(thiophen-3-yl)-4-(thiophen-3-yl-S,S-dioxo)pentan-3-one
  • Pentanones
  • Thiophenes