Adducts of thianthrene- and phenoxathiin cation radical salts with symmetrical alkynes. Structure and formation of cumulenes on alumina leading to α-diketones, α-hydroxyalkynes, and α-acetamidoalkynes

Henry J. Shine, Paramashivappa Rangappa, John N. Marx, Dennis C. Shelly, Teyeb Ould-Ely, Kenton H. Whitmire

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16 Citations (Scopus)

Abstract

Thianthrene cation radical tetrafluoroborate (Th.+BF 4-) added to 2-butyne, 3-hexyne, 4-octyne, and 5-decyne in MeCN to form trans bisadducts E(Th+)C=C(Th+)R, where E = Me, Et, Pr, Bu (7a-d). Phenoxathiin cation radical tetrafluoroborate (PO .+BF4-) added similarly to the last three alkynes to form adducts E(PO+)C=C(PO+)E, 8b-d. Cyclic monoadducts were not found. The trans structures of 7 and 8 were deduced with X-ray crystallography (7c) and NME spectroscopy. When solutions of adducts in CHCl3 and MeCN were deposited on activated alumina, elimination of thianthrene (Th) and phenoxathiin (PO) occurred almost quantitatively. Detailed studies with (7b-d) indicated that a cumulene (15) was formed by the elimination of Th and that 15 was subsequently converted into small amounts of other products. In CHCl3, these products were the respective alkyne, thianthrene 5-oxide, an α-diketone (11), an α-hydroxyalkyne (12), and hydrogen. The same products were formed in MeCN along with an α-acetamidoalkyne (13). The formation of 15 and products derived from it is explained and was confirmed by preparation and reactions of 2,3,4-hexatriene.

Original languageEnglish
Pages (from-to)3877-3883
Number of pages7
JournalJournal of Organic Chemistry
Volume70
Issue number10
DOIs
Publication statusPublished - May 13 2005

ASJC Scopus subject areas

  • Organic Chemistry

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