Five-membered ring systems with O and N atoms

Primary nitro compounds: progress in the synthesis of isoxazoles by condensation with aldehydes or activated ketones

“…Most of these reactions have been extensively discussed in many reviews and book chapters 7 and their recent development has been described. 8…”

Exploring the Reactivity of Substituted [(Allyloxy)methyl]phosphonates in Cycloaddition and Coupling Reactions

“…The 1,3-dipolar cycloaddition process involving nitrile oxide, nitrile imine, and nitrone leads to the formation of five-membered heterocycles, which are present in a wide range of molecules with specific pharmaceutical and biological activities. 7,8 Isoxazolines, pyrazolines, and isoxazolidines are nitrogen-containing heterocycles [9][10][11] found in a vast collection of biologically interesting natural or synthetic compounds (Figure 1). [12][13][14] Transition-metal-catalyzed methodologies are very efficient approaches to construct novel carbon-carbon bonds in a molecule.…”