Lewis Acid Catalyzed Regio- and Diastereoselective Synthesis of Spiroisoxazolines via One-Pot Sequential Knoevenagel Condensation/1,3-Dipolar Cycloaddition Reaction

• DOI: 10.1055/s-0037-1610676
• Publication Date: 2019-01-18T04:30:11Z
• Authors: Ayoob Bazgir; Hossein Yazdani
• Keywords: Knoevenagel condensation; Oxindole; Isoxazole; Benzothiazole; Coupling reaction

A ZnCl2-catalyzed regio- and diastereoselective one-pot sequential Knoevenagel condensation/1,3-dipolar cycloaddition reaction of CH acids (oxindole, 1,3-indandione, 3H-pyrazol-3-one), aldehydes, dibromoformaldoxime has been established. The method allows the synthesis diversely functionalized spiroisoxazolines in good isolated yields under mild conditions. Moreover, preparation spiroindene-isoxazole-1,3-diones containing benzoimidazole or benzothiazole moieties as new ligands for metal-catalyzed coupling reactions C–H activation is demonstrated.