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Substituted ?-Alkylidene Cyclopentenones via the Intramolecular Reaction of Vinyl Cations with Alkenes.

ABSTRACT: Substituted ?-alkylidene cyclopentenones are formed in up to 93% yield by the intramolecular capture of vinyl cations with pendent alkenes. An increased level of substitution at the ?-position of the ?-hydroxy-?-diazoketone starting material changed the course of the reaction to instead give a lactone product. A reaction path that involves bond reorganization via an acylium ion intermediate is proposed to explain these results. Substrate scope studies showed that more stable vinyl cations gave higher ?-alkylidene cyclopentenone yields. This study provides a mild and efficient method to form ?-alkylidene cyclopentenones that complements C-H insertion and Nazarov cyclization strategies.

SUBMITTER: Hensinger MJ

PROVIDER: S-EPMC7045725 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Substituted α-Alkylidene Cyclopentenones via the Intramolecular Reaction of Vinyl Cations with Alkenes.

Hensinger Magenta J MJ Dodge Nicholas J NJ Brewer Matthias M

Organic letters 20191224 2

Substituted α-alkylidene cyclopentenones are formed in up to 93% yield by the intramolecular capture of vinyl cations with pendent alkenes. An increased level of substitution at the β-position of the β-hydroxy-α-diazoketone starting material changed the course of the reaction to instead give a lactone product. A reaction path that involves bond reorganization via an acylium ion intermediate is proposed to explain these results. Substrate scope studies showed that more stable vinyl cations gave h ...[more]

PMID: 31873030

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