Radical Sequential Processes Promoted by 1,5-Radical Translocation Reaction: Formation and [3 + 2] Anulation of Alkenesulfanyl Radicals
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Updated: Oct 3, 2026

Efficient Synthesis of Polyfunctionalized Benzenes in Water via Persulfate-promoted Benzannulation of α,β-Unsaturated Compounds and Alkynes
Published on: December 16, 2019
Laura Capella1, Pier Carlo Montevecchi, Maria Luisa Navacchia
1Dipartimento di Chimica Organica "A. Mangini", Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
Abstract:
Radical addition of 2-substituted ethanethiols 1-5 to alkyl-, dialkyl-, and phenylacetylenes affords the corresponding beta-sulfanylalkenyl radicals, which can undergo 1,5-radical translocation (RT reaction) in competition with intermolecular hydrogen abstraction (HA reaction). The RT reaction is the first step of a sequential radical process leading to alkenesulfanyl radicals through an "intermolecular sulfanyl radical transaddition" from an alkene to an alkyne molecule. Alkenesulfanyl radicals can undergo a regioselective [3 + 2] anulation reaction with a CC triple bond, eventually leading to thiophene products through 5-endo cyclization of vinyl radicals onto CC double bond. The effect of the nature of ethanethiol and alkyne substituents on the RT/HA ratio has been investigated, and results will be discussed.
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