Photolyses of organocobaloxime having aralkyl and (alkylthio)carbonyl groups on the β-position. A radical reaction involving the thioester group

Masaru Tada, Tatsuya Nakamura, Mitsuhiro Matsumoto

    Research output: Contribution to journalArticle

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    Abstract

    [2-[(Alkylthio)carbonyl]-4-mesityl-2-methylbutyl]cobaloxime (1), [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-5-phenylpentyl]cobaloxime (2), and [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-4-mesitylbutyl]cobaloxime (3) were photolyzed to produce pairs of organo radicals and cobaloxime(II) radicals by the rupture of a carbon-cobalt σ-bond. The organo radicals collapsed into hydrogen abstraction products 4, 7, and 10, a thioester rearranged product, 5, an intramolecular 1,5-hydrogen shift product, 8, a thioester elimination product, 11, and β-thiolactones 6, 9, and 12. The β-thiolactones resulted by the radical substitution on sulfur of the thioester and are the major products from the cobaloximes that have a (tert-butylthio)carbonyl group. For the thioester rearrangement a stepwise mechanism is proposed, which involves an internal radical attack on sulfur followed by the bond switching from alkylthio to alkylcarbonyl (Scheme V). Last, the possible involvement of cobaloxime(II) in this thioester rearrangement is discussed. The cobalt complex is considered to facilitate the rearrangement by the interaction between sulfur and cobalt(II) radical species.

    Original languageEnglish
    Pages (from-to)4647-4652
    Number of pages6
    JournalJournal of the American Chemical Society
    Volume110
    Issue number14
    Publication statusPublished - 1988

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    Photolysis
    Cobalt
    Sulfur
    Hydrogen
    Substitution reactions
    Carbon
    cobaloxime
    Rupture

    ASJC Scopus subject areas

    • Chemistry(all)

    Cite this

    Photolyses of organocobaloxime having aralkyl and (alkylthio)carbonyl groups on the β-position. A radical reaction involving the thioester group. / Tada, Masaru; Nakamura, Tatsuya; Matsumoto, Mitsuhiro.

    In: Journal of the American Chemical Society, Vol. 110, No. 14, 1988, p. 4647-4652.

    Research output: Contribution to journalArticle

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    abstract = "[2-[(Alkylthio)carbonyl]-4-mesityl-2-methylbutyl]cobaloxime (1), [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-5-phenylpentyl]cobaloxime (2), and [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-4-mesitylbutyl]cobaloxime (3) were photolyzed to produce pairs of organo radicals and cobaloxime(II) radicals by the rupture of a carbon-cobalt σ-bond. The organo radicals collapsed into hydrogen abstraction products 4, 7, and 10, a thioester rearranged product, 5, an intramolecular 1,5-hydrogen shift product, 8, a thioester elimination product, 11, and β-thiolactones 6, 9, and 12. The β-thiolactones resulted by the radical substitution on sulfur of the thioester and are the major products from the cobaloximes that have a (tert-butylthio)carbonyl group. For the thioester rearrangement a stepwise mechanism is proposed, which involves an internal radical attack on sulfur followed by the bond switching from alkylthio to alkylcarbonyl (Scheme V). Last, the possible involvement of cobaloxime(II) in this thioester rearrangement is discussed. The cobalt complex is considered to facilitate the rearrangement by the interaction between sulfur and cobalt(II) radical species.",
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    T1 - Photolyses of organocobaloxime having aralkyl and (alkylthio)carbonyl groups on the β-position. A radical reaction involving the thioester group

    AU - Tada, Masaru

    AU - Nakamura, Tatsuya

    AU - Matsumoto, Mitsuhiro

    PY - 1988

    Y1 - 1988

    N2 - [2-[(Alkylthio)carbonyl]-4-mesityl-2-methylbutyl]cobaloxime (1), [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-5-phenylpentyl]cobaloxime (2), and [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-4-mesitylbutyl]cobaloxime (3) were photolyzed to produce pairs of organo radicals and cobaloxime(II) radicals by the rupture of a carbon-cobalt σ-bond. The organo radicals collapsed into hydrogen abstraction products 4, 7, and 10, a thioester rearranged product, 5, an intramolecular 1,5-hydrogen shift product, 8, a thioester elimination product, 11, and β-thiolactones 6, 9, and 12. The β-thiolactones resulted by the radical substitution on sulfur of the thioester and are the major products from the cobaloximes that have a (tert-butylthio)carbonyl group. For the thioester rearrangement a stepwise mechanism is proposed, which involves an internal radical attack on sulfur followed by the bond switching from alkylthio to alkylcarbonyl (Scheme V). Last, the possible involvement of cobaloxime(II) in this thioester rearrangement is discussed. The cobalt complex is considered to facilitate the rearrangement by the interaction between sulfur and cobalt(II) radical species.

    AB - [2-[(Alkylthio)carbonyl]-4-mesityl-2-methylbutyl]cobaloxime (1), [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-5-phenylpentyl]cobaloxime (2), and [2-[(alkylthio)carbonyl]-2-(ethoxycarbonyl)-4-mesitylbutyl]cobaloxime (3) were photolyzed to produce pairs of organo radicals and cobaloxime(II) radicals by the rupture of a carbon-cobalt σ-bond. The organo radicals collapsed into hydrogen abstraction products 4, 7, and 10, a thioester rearranged product, 5, an intramolecular 1,5-hydrogen shift product, 8, a thioester elimination product, 11, and β-thiolactones 6, 9, and 12. The β-thiolactones resulted by the radical substitution on sulfur of the thioester and are the major products from the cobaloximes that have a (tert-butylthio)carbonyl group. For the thioester rearrangement a stepwise mechanism is proposed, which involves an internal radical attack on sulfur followed by the bond switching from alkylthio to alkylcarbonyl (Scheme V). Last, the possible involvement of cobaloxime(II) in this thioester rearrangement is discussed. The cobalt complex is considered to facilitate the rearrangement by the interaction between sulfur and cobalt(II) radical species.

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