Allylic Amidation of Olefins by Ene Reaction of Acylnitroso Compounds Generated in situ by Oxidation of Hydroxamic Acids

Advancements in the Nascent Nitroso-Ene Reaction

“…Adam et al established that good yields of the intermediary acylnitroso compound can be achieved under mild conditions, as demonstrated by the ene reactions with appropriate olefins (Scheme 6). 39 For ease of handling, the more labile N-allylhydroxamic acids were acetylated to the more persistent O-acetylated derivatives. Quadrelli et al generated nitroso reagents via oxidation of nitrile oxides with N-methylmorpholine N-oxide (NMO) and the subsequent ene reactions worked well with tetraand trisubstituted ethylenes (Scheme 7).…”

Developments in Nitrosocarbonyl Chemistry: Mild Oxidation of N-Substituted Hydroxylamines Leads to New Discoveries

“…The first example of single-pot oxidative generation of nitrosocarbonyl compounds for the ene reaction was reported by Adam and co-workers in 1999. 22 The method involves the slow addition of the hydroxamic acid to iodosobenzene diacetate and three equivalents of the olefin. The reaction is high-yielding for simple dienes with a variety of hydroxamic acids ( A number of research groups have reported examples of the catalytic oxidation of hydroxamic acids employing transition metals and stoichiometric peroxides for both the Diels-Alder 13 and the ene reaction.…”

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

“…As part of our research on the syntheses of heterocycles by iodine(III)-mediated/catalyzed oxidative cycloaddition reactions [ 17 – 19 ], we have found that iodine(III) reagents are effective in the oxidation of N–O bonds of oximes in the cycloaddition reaction of in situ formed nitrile oxides [ 20 – 21 ]. Although Adam and Bottke’s group have demonstrated that (diacetoxyiodo)benzene (DIB) and iodosylbenzene are applicable to the ene reactions of acylnitroso species derived from hydroxamic acids [ 22 ], the iodine(III)-mediated oxidative cycloaddition reaction of hydroxamic acids with dienes is still unknown. Herein, we report the HDA reaction of acylnitroso species generated from hydroxamic acids by [bis(trifluoroacetoxy)iodo]benzene (BTI) or DIB.…”