First Example of Diels-Alder Reaction of 4-(1-Ethenylsubstituted)-3-methylisoxazoles with Acetylenedicarboxylates
摘要:
The first example of a [4+2] cycloaddition reaction of 4-(1-ethenylsubstituted)isoxazoles with acetylenedicarboxylates is reported, while the corresponding 5-substituted isomers do not react with the same dienophile; density functional theory (DFT) calculation indicate the electronic origin of the different behaviour.
Regioselective Synthesis of 4-Acetyl-and 5-Acetyl-3-methylisoxazole: Their Conversion into Silyl-and Methyl Enol Ethers
作者:Stefano Chimichi、Barbara Cosimelli
DOI:10.1080/00397919208021114
日期:1992.11
(E)-4-methoxy-3-buten-2-one to give 5-acetyl-2 and 4-acetyl-3-methylisoxazole 3, respectively. Treatment of ketones 2 and 3 with trimethylsilyl trifluoromethanesulfonate gave the silyl enolethers 4 and 5, whereas the methylenolethers 8 and 9 were obtained via elimination of methanol from the corresponding dimethyl ketals.
The first example of a [4+2] cycloaddition reaction of 4-(1-ethenylsubstituted)isoxazoles with acetylenedicarboxylates is reported, while the corresponding 5-substituted isomers do not react with the same dienophile; density functional theory (DFT) calculation indicate the electronic origin of the different behaviour.