13130-16-0Relevant articles and documents
Polymer-supported copper complex for the direct synthesis of O-aryloxime ethers via cross-coupling of oximes and arylboronic acids
Wang, Liang,Huang, Chengyan,Cai, Chun
experimental part, p. 532 - 536 (2010/07/16)
L-proline functionalized chloroacetylated polystyrene supported copper (II) complex was prepared and found to be effective for the cross-coupling reaction between aromatic oximes and arylboronic acids under mild conditions. Only catalytic amount of cataly
Efficient synthesis of benzofurans utilizing [3,3]-sigmatropic rearrangement triggered by N-trifluoroacetylation of oxime ethers: Short synthesis of natural 2-arylbenzofurans
Takeda, Norihiko,Miyata, Okiko,Naito, Takeaki
, p. 1491 - 1509 (2008/09/19)
A new synthetic method for the preparation of benzofurans has been developed. The key step of this method is the [3,3]-sigmatropic rearrangement of N-trifluoroacetyl-ene-hydroxylamines, which was triggered by acylation of oxime ethers. TFAA has been proved to be the best reagent to induce [3,3]-sigmatropic rearrangement for the synthesis of cyclic or acyclic dihydrobenzofurans. On the other hand, the TFAT-DMAP system is found to be the most effective for constructing various benzofurans. Synthetic utility of this reaction is demonstrated by the short synthesis of natural benzofurans without protection of the hydroxy group. The synthesis of Stemofuran A was accomplished via condensation of ketones with aryloxyamine and subsequent reaction with TFAT-DMAP in a four-step synthesis with 72% overall yield. Similarly, Eupomatenoid 6 and Coumestan were synthesized through the reaction of oxime ether with TFAT-DMAP. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Thermolyses of O-Phenyl Oxime Ethers. A New Source of Iminyl Radicals and a New Source of Aryloxyl Radicals
Blake, Jessie A.,Pratt, Derek A.,Lin, Shuqiong,Walton, John C.,Mulder, Peter,Ingold
, p. 3112 - 3120 (2007/10/03)
Six O-phenyl ketoxime ethers, RR′C=NOPh 1-6, with RR′= diaryl, dialkyl, and arylalkyl, together with N-phenoxybenzimidic acid phenyl ether, PhO(Ph)C=NOPh, 7, have been shown to thermolyze at moderate temperatures with "clean" N-O bond homolyses to yield iminyl and phenoxyl radicals, RR′C=N. and PhO.. Since 1-6 can be synthesized at room temperature, these compounds provide a new and potentially useful source of iminyls for syntheses. The iminyl from 7 undergoes a competition between β-scission, to PhCN and PhO., and cyclization to an oxazole. Rate constants, 106 k/s-1, at 90 °C for 1-6 range from 4.2 (RR′ = 9-fluorenyl) to 180 (RR′ = 9-bicyclononanyl), and that for 7 is 0.61. The estimated activation enthalpies for N-O bond scission are in satisfactory agreement with the results of DFT calculations of N-O bond dissociation enthalpies, BDEs, and represent the first thermochemical data for any reaction yielding iminyl radicals. The small range in k (N-O homolyses) is consistent with the known σ structure of these radicals, and the variations in k and N-O BDEs with changes in RR′ are rationalized in terms of iminyl radical stabilization by hyperconjugation: RR′C=N . ? R.R′C≡N. Calculated N-H BDEs in the corresponding RR′C= NH are also presented.
Studies on the Preparation of N-Alkyl-O-phenylhydroxylamines
Sheradsky, Tuvia,Nov, Eliahu
, p. 2781 - 2786 (2007/10/02)
Several possible routes to the title compounds have been investigated.The reaction of N-hydroxycarbamates (1) with diphenyliodonium bromide gave, unexpectedly, N-hydroxy-N-phenylcarbamates (2), while N-methyl-N-hydroxycarbamates (6) gave 2-(N-methyl-N-alkoxycarbonylamino)phenols (7).Mechanistic aspects of the N-arylations and subsequent rearrangements are discussed.The desired N-alkyl-O-phenylhydroxylamines were obtained by the reduction of O-phenyloximes (15) with sodium cyanoborohydride.
