“…As one type of electron-deficient alkenes, 4-nitro-5-styrylisoxazoles, in which alkenes are installed on a 4-nitroisoxazole ring, have attracted much attention in various transformations for synthesis of isoxazole derivatives with structural diversity. They have extensively been applied in many annulation reactions such as 1,3-dipolar [3 + 2] cycloaddition of azomethine ylides, [3 + 2] cycloaddition of tosylmethyl isocyanide, N-heterocyclic carbene-catalyzed [3 + 2] and [4 + 2] annulation reactions of enals, l -proline-catalyzed one-pot three-component aza-Diels–Alder reactions, phase-transfer-catalyzed enantioselective cyclopropanation and [4 + 2] annulation, quinine-catalyzed [3 + 2] annulation of 3-isothiocyanato oxindoles, quinidine-derived thiourea-catalyzed [4 + 2] annulation of chromone-based oxindoles, cinchona-derived squaramide/base-catalyzed [2 + 2 + 2] annulation of β-dicarbonyl compounds and β-nitroalkenes, trienamine-mediated [4 + 2]-cycloaddition, and base-promoted [3 + 2] annulation of 1,4-dithiane-2,5-diol . With these synthetic reactions, diverse carbocyclic and heterocyclic compounds have been prepared.…”