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Updated: Jun 25, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Reaction of dicarbomethoxycarbene with thiophene derivatives
William S Jenks1, Melanie J Heying, Stacey A Stoffregen
1Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, USA. wsjenks@iastate.edu
Abstract:
Photolysis of derivatives of dimethylmalonate thiophene-S,C-ylide provides dicarbomethoxycarbene, which can react with thiophene to form dimethyl (2-thienyl)malonate. By generation of dicarbomethoxycarbene from the dibenzothiophene-based ylide in neat thiophene, it is shown that the thienylmalonate is not a product of rearrangement of the thiophene ylide, in contrast to thermolysis results. Formation of the thienylmalonate is suppressed by substitution of any sort in the 2- and 5-positions on the thiophene and by substitution with an electron-withdrawing substituent.
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