Metal-assisted Lossen Rearrangement

• Published in: Journal of organic chemistry Vol. 77; no. 6; pp. 2829 - 2836
• Main Authors: JASIKOVA, Lucie, HANIKYROVA, Eva, SKRIBA, Anton, JASIK, Juraj, ROITHOVA, Jana
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 16-03-2012
• Subjects: Chemistry; Exact sciences and technology; Kinetics and mechanisms; Organic chemistry; Reactivity and mechanisms; Chemical rearrangement; Potassium complex; Zinc complex; Hydroxamic acid; Metal complex; Transition metal Complexes; Acid catalysis; Organic carbamate; Metal Complexes; Characterization; Computational chemistry; Anions; IRMPD; Reaction mechanism; Lossen rearrangement; Zinc Complexes; Mass spectrometry; Deprotonation
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo300031f

A new reaction mechanism for the Lossen rearrangement of hydroxamic acids catalyzed by basic salts is presented. It is shown that the rearrangement proceeds in metal complexes of deprotonated hydroxamic acids. The deprotonation can occur either at the oxygen atom (observed for the zinc complexes) or at the nitrogen atom (observed for the potassium complexes). Both anionic forms are characterized by infrared multiphoton dissociation spectroscopy. The rearrangements proceed from the reactive N-deprotonated metal hydroxamates and lead to metal carbamates. The mechanism is elucidated by computational chemistry, mass-spectrometric studies, and preparative experiments.