New Isoxazole-Substituted Aryl Iodides: Metal-Free Synthesis, Characterization and Catalytic Activity

A series of new isoxazole-substituted aryl iodides 1 a-1 d have been synthesized by DIB-mediated [3+2] cycloaddition reaction of 2-iodo-1,3-bis(prop-2-yn-1-yloxy) benzene (4) with corresponding benzaldehyde oximes 5 a-5 d. Structure of the synthesized aryl iodides 1 were characterized by IR, 1H NMR, 13C NMR and HRMS. The structure of 1 a was also confirmed by single-crystal X-ray crystallography. Further, catalytic activity of iodoarenes 1 a-1 d was screened for the oxidation of hydroquinones and sulfides. On oxidation using aryl iodides 1 with m-CPBA as terminal oxidant, hydroquinones afforded benzoquinones while sulfides gave corresponding sulfoxides in good to excellent yields. Iodoarene 1 b showed the best catalytic activity for the oxidation of sulfides and hydroquinones. Moreover, iodoarene 1 b, was also utilized for alpha-oxytosylation of acetophenones. New Isoxazole bearing aryl iodides 1 a-1 d were synthesized via metal-free [3+2] cycloaddition and their catalytic activity was investigated towards oxidation of hydroquinone, sulfides and alpha-oxytosylation of acetophenones.image