Experimental and Computational Investigations of the Reactions between α,ß-Unsaturated Lactones and 1,3-Dienes by Cooperative Lewis Acid/Brønsted Acid Catalysis.
Angew Chem Int Ed Engl
; 59(42): 18709-18716, 2020 10 12.
Article
em En
| MEDLINE
| ID: mdl-32567075
ABSTRACT
The reactions of α,ß-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 (40-78 %) over three steps. DFT-calculations provide insights into the reaction mechanism and support the theory of a stepwise reaction.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2020
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Article