Iodine(III)-Mediated Oxy-fluorination of Alkenyl Oximes: An Easy Path to Monofluoromethyl-Substituted Isoxazolines
摘要:
A highly regioselective intramolecular oxy-fluorination of alkenyl oximes was achieved. This new transformation represents an efficient method for the preparation of monofluoromethyl-substituted isoxazolines. The synthetic application of the oxy-fluorination product was demonstrated by a one-step synthesis of monofluoromethyl-substituted beta-hydroxyl ketone derivatives.
Oxime Radical Promoted Dioxygenation, Oxyamination, and Diamination of Alkenes: Synthesis of Isoxazolines and Cyclic Nitrones
作者:Bing Han、Xiu-Long Yang、Ran Fang、Wei Yu、Chao Wang、Xiao-Yong Duan、Shuai Liu
DOI:10.1002/anie.201203799
日期:2012.8.27
Up the tempo: The intramolecular addition of oxime radicals to CC bonds was achieved by using DEAD and TEMPO to give 4,5‐dihydroisoxazoles as a result of a CO bond‐forming, 5‐exo‐trig cyclization. γ,δ‐Unsaturated ketoximes also reacted to afford cyclicnitrones through CN bond formation. The reactions offer a metal‐free approach for the vicinal difunctionalization of unactivated alkenes.
A mild and efficient copper-catalyzed trifluoromethylation reaction which involves the cyclization of oximes has been developed. This method provides a convenient access to a variety of useful CF3-containing 4,5-dihydroisoxazoles by constructing a C–CF3 bond and a C–O bond in one step.
A novel and facile copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates for the synthesis of 2-arylpyrroles has been developed. The reaction tolerates a range of functional groups and is a practical procedure for rapid synthesis of 2-arylpyrroles in high yields under mild conditions.
Transition-metal-free oxychlorination of alkenyl oximes: in situ generated radicals with tert-butyl nitrite
作者:Xiao-Wei Zhang、Zu-Feng Xiao、Mei-Mei Wang、Yan-Jun Zhuang、Yan-Biao Kang
DOI:10.1039/c6ob01374k
日期:——
Oxychlorination of alkenyl oximes is harder compared to the analogous oxybromination or oxyiodination because of the difficulty associated with the formation of chlorine cations or radicals. A transition-metal-free oxychlorination of alkenyl oximes has been developed, using t-BuONO as a dual oxidant and AlCl3 as a chlorine source. This convenient and practical method has been used to construct chloroisoxazolines
Room temperature iron(<scp>ii</scp>)-catalyzed radical cyclization of unsaturated oximes with hypervalent iodine reagents
作者:Shichao Yang、Hongji Li、Pinhua Li、Jingya Yang、Lei Wang
DOI:10.1039/c9ob02424g
日期:——
Here, we disclose an iron(ii)-catalyzed I-O bond cleavage of Koser's hypervalent iodine reagents (HIRs) that initiated the radical cyclization of unsaturated oximes at room temperature. This strategy is successfully applied for the construction of the isoxazoline backbone in an efficient manner. In particular, the direct introduction of a TsO group into products facilitates their late-stage transformations