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Experimental and Computational Investigations of the Reactions between ?,?-Unsaturated Lactones and 1,3-Dienes by Cooperative Lewis Acid/Bronsted Acid Catalysis.

ABSTRACT: The reactions of ?,?-unsaturated ?-lactones with activated dienes such as 1,3-dimethoxy-1-[(trimethylsilyl)oxy]-1,3-butadiene (Brassard's diene) are barely known in literature and show high potential for the synthesis of isocoumarin moieties. An in-depth investigation of this reaction proved a stepwise mechanism via the vinylogous Michael-products. Subsequent cyclisation and oxidation by LHMDS and DDQ, respectively, provided six mellein derivatives (30-84?%) and four angelicoin derivatives (40-78?%) over three steps. DFT-calculations provide insights into the reaction mechanism and support the theory of a stepwise reaction.

SUBMITTER: Weber A

PROVIDER: S-EPMC7589441 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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Experimental and Computational Investigations of the Reactions between α,β-Unsaturated Lactones and 1,3-Dienes by Cooperative Lewis Acid/Brønsted Acid Catalysis.

Weber Anja A Breugst Martin M Pietruszka Jörg J

Angewandte Chemie (International ed. in English) 20200818 42

The reactions of α,β-unsaturated δ-lactones with activated dienes such as 1,3-dimethoxy-1-[(trimethylsilyl)oxy]-1,3-butadiene (Brassard's diene) are barely known in literature and show high potential for the synthesis of isocoumarin moieties. An in-depth investigation of this reaction proved a stepwise mechanism via the vinylogous Michael-products. Subsequent cyclisation and oxidation by LHMDS and DDQ, respectively, provided six mellein derivatives (30-84 %) and four angelicoin derivatives (40-7 ...[more]

PMID: 32567075

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