Oxidative cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine(III) reagents.

[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels-Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the oxidative dearomatization of guaiacols.

Tetra-n-butylammonium Iodide Catalyzed C-H Azidation of Aldehydes with Thermally Stable Azidobenziodoxolone.

Tetra-n-butylammonium iodide can efficiently catalyze direct azidation of aldehyde C-H bonds with thermally stable azidobenziodoxolone at room temperature. Compared to conventional methods, which require excessive amounts of highly explosive azide sources, this is a safe and convenient procedure.