芳香醛和脂肪醛与异恶唑的光环加成：环加成反应活性和稳定性研究。

University of Cologne, Department of Chemistry, Organic Chemistry, Greinstr. 4, D-50939 Köln, Germany;

Beilstein J Org Chem. 2011 Jan 26;7:127-34. doi: 10.3762/bjoc.7.18.

The first photocycloadditions of aromatic and aliphatic aldehydes to methylated isoxazoles are reported. The reactions lead solely to the exo-adducts with high regio- and diastereoselectivities. Ring methylation of the isoxazole substrates is crucial for high conversions and product stability. The 6-arylated bicyclic oxetanes 9a-9c were characterized by X-ray structure analyses and showed the highest thermal stabilities. All oxetanes formed from isoxazoles were highly acid-sensitive and also thermally unstable. Cleavage to the original substrates is dominant and the isoxazole derived oxetanes show type T photochromism.

首次报道了芳香醛和脂肪醛与甲基异恶唑的光环加成反应。这些反应仅生成具有高区域和立体选择性的反式加成产物。异恶唑底物的环甲基化对于高转化率和产物稳定性至关重要。通过 X 射线结构分析对 6-芳基双环氧杂环丁烷 9a-9c 进行了表征，它们表现出最高的热稳定性。所有由异恶唑形成的氧杂环丁烷都对酸高度敏感，热稳定性也差。以裂解回原底物为主，异恶唑衍生的氧杂环丁烷呈现 T 型光致变色性。