AbstractThe classical Lossen rearrangement converts activated hydroxamic acids to isocyanates that form numerous products upon their reaction with nucleophiles. We report a simple and highly efficient method of using Heck reaction conditions to initiate Lossen rearrangements of hydroxamic acids. In addition, Lossen rearrangements occur in the presence of palladium(II) acetate or triethylamine, components of the Heck reaction, alone. A potential mechanism is provided to explain this reactivity and these results show that Heck reactions and Lossen rearrangements occur under the same conditions and may provide new methods for facile initiation of Lossen rearrangements.magnified image
Generation of nitrenes from alkanamidates and alkanesulphonamidates
作者:P. Robson、P. R. H. Speakman
DOI:10.1039/j29680000463
日期:——
sulphonyl nitrene which was trapped by nucleophiles. The sulphonamidate was stable towards u.v. radiation. The alkanamidates decomposed thermally to give undecyl isocyanate by a concerted intramolecular process which did not involve the formation of a nitrene intermediate. Dodecanoyl nitrene, generated by photolysis of the alkanamidated in dimethyl sulphoxide, has been compared with similar nitrenes obtained
The Mechanism of Dephosphorylation of Bis(2,4-dinitrophenyl) Phosphate in Mixed Micelles of Cationic Surfactants and Lauryl Hydroxamic Acid
作者:Marcelo Silva、Renata S. Mello、M. Akhyar Farrukh、Janio Venturini、Clifford A. Bunton、Humberto M. S. Milagre、Marcos N. Eberlin、Haidi D. Fiedler、Faruk Nome
DOI:10.1021/jo9017638
日期:2009.11.6
involving concurrent nucleophilicattack by hydroxamateion (i) on the aromatic carbon, giving an intermediate that decomposes to undecylamine and 2,4-dinitrophenol, and (ii) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement yielding a series of derivatives including N,N-dialkylurea, undecylamine, undecyl isocyanate, and carbamyl hydroxamate.