Aqueous‐Mediated Microwave Synthesis of Novel Tetrahydrospiro [Chromeno‐Isoxazole‐Indolinone] Derivatives <i>via</i> 1,3‐Dipolar Cycloaddition Reaction

Abstract A regiospecific approach has been developed for the synthesis of 2,2‐disubstituted 2‐phenyl‐2,3 a ,4,9 b ‐tetrahydrospiro[chromeno[4,3‐ d ]isoxazole‐1,3’‐indolin]‐2’‐one derivatives via 1,3‐dipolar cycloddition reaction. This one‐pot, two‐component synthesis involves 2 H ‐chromene and N ‐arylisatin nitrones in aqueous medium, promoting a green synthesis by minimizing the use of hazardous reagents and enhancing the sustainability of synthesis. The cycloadducts, which feature a spiro center, are efficiently obtained under both conventional method and microwave irradiation. The newly developed derivatives were characterized using 1 H, 13 C NMR, as well as HRMS spectra. Furthermore, the structure of compound 16 a was unambiguously confirmed through single‐crystal X‐ray analysis.