School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada Kami, Kochi 782-8502, Japan.
Org Biomol Chem. 2012 Mar 14;10(10):1987-91. doi: 10.1039/c2ob06925c. Epub 2012 Jan 27.
A new protocol for synthesizing different functionalized isoxazoles is provided. Carbamoylnitrile oxide generated from nitroisoxazolone underwent inverse electron-demand 1,3-dipolar cycloaddition with 1,3-dicarbonyl compounds in the presence of magnesium acetate that formed magnesium enolate in situ. Although electron-deficient trifluoroacetoacetate did not undergo this cycloaddition under the same conditions, conversion to sodium enolate furnish the corresponding bis-functionalized trifluoromethylisoxazole. The DFT calculations using B3LYP 6-31G+(d,p) also supported the aforementioned reactivity.
提供了一种合成不同功能化异恶唑的新方法。硝基亚唑酮生成的碳酰亚胺氧化物在醋酸镁的存在下与 1,3-二羰基化合物经历逆向电子需求 1,3-偶极环加成反应，在原位形成镁烯醇盐。尽管缺电子的三氟乙酰乙酸在相同条件下不进行此环加成反应，但转化为钠盐烯醇盐可得到相应的双官能化三氟甲基异恶唑。使用 B3LYP 6-31G+(d,p)进行的 DFT 计算也支持了上述反应性。
