Spectroscopic characterization of triplet 3-thienylcarbene, its substituted analogs, and their rearrangement products

ORGN 489

Caroline R. Pharr, crpharr@wisc.edu, Department of Chemistry, University of Wisconsin - Madison, 1101 University Avenue, Madison, WI 53704 and Robert J. McMahon, mcmahon@chem.wisc.edu, Department of Chemistry, University of Wisconsin, 1101 University Ave, Madison, WI 53706.
Although thienyl and furanyl carbenes have long been postulated as intermediates in organic chemistry, and have been the subject of considerable theoretical interest, they have eluded spectroscopic detection.We now report the detection and characterization of triplet 3-thienylcarbene, along with methyl and methyl-d3 substituted derivatives, by IR, UV-vis, and EPR spectroscopy in cryogenic matrices.Triplet 3-thienylcarbene shows two rotamers in the EPR spectrum.The spectra reveal the apparent heavy atom influence of sulfur. The methyl substituted derivatives both show only one rotamer in their EPR spectrum.UV-vis spectra also are characteristic of triplet carbene intermediates. Photochemical reactions of this family of thiophenes and furans in cryogenic matrices will also be described.

 

Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Organic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007