29373-01-1Relevant academic research and scientific papers
Copper-catalyzed radical oxyallylation of olefins for the construction of alkene-containing isoxazolines
He, Xiaoxue,Qian, Lijie,Dai, Yuyu,Yan, Xinhuan,Li, Xiaoqing,Xu, Xiangsheng
, (2021/05/31)
A radical-mediated approach to alkene oxyallylation using allylic oximes is described. The reaction proceeds under copper-catalytic redox-neutral conditions and tolerates various functional groups. This protocol thus enables the synthesis of structurally valuable isoxazolines and the introduction of a versatile olefin motif in a single step.
Copper-Catalyzed Aerobic Cyclization of β,γ-Unsaturated Hydrazones with Concomitant CC Bond Cleavage
Fan, Zhenwei,Feng, Jiahao,Hou, Yuchen,Rao, Min,Cheng, Jiajia
, p. 7981 - 7985 (2020/11/02)
A Cu-catalyzed aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant CC bond cleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible byproducts. The advantages of this reaction include operational simplicity, a broad reaction scope, and a mild selective reaction process.
Palladium-Catalyzed Allylic Alkylation of 2-Aryl-1,3-Dithianes, an Umpolung Synthesis of β,γ-Unsaturated Ketones
Trongsiriwat, Nisalak,Li, Minyan,Pascual-Escudero, Ana,Yucel, Baris,Walsh, Patrick J.
supporting information, p. 502 - 509 (2018/12/11)
Palladium-catalyzed allylic alkylation of 2-aryl-1,3-dithianes at room temperature is described. A variety of cyclic and acyclic electrophiles successfully coupled with in-situ generated 2-sodio-1,3-dithiane nucleophiles to afford the allylated products in good to excellent yields (25 examples). Deprotection of these products leads to valuable β,γ-unsaturated ketones. Direct synthesis of such β,γ-unsaturated ketones via a one-pot allylation-oxidation protocol is also presented. Investigation into the stereochemistry of the allylation reaction revealed that the 2-sodio-1,3-dithiane nucleophile behaves as a “soft” nucleophile, which underwent external attack on the π-allyl palladium complex to provide retention of stereochemistry (double inversion pathway). Additionally, the utility of this method was demonstrated through a sequential one-pot allylation-Heck cyclization to produce asterogynin derivatives, which are important bioactive compounds in medicinal chemistry. (Figure presented.).
Iminoxyl Radical-Promoted Oxycyanation and Aminocyanation of Unactivated Alkenes: Synthesis of Cyano-Featured Isoxazolines and Cyclic Nitrones
Chen, Fei,Zhu, Fei-Fei,Zhang, Man,Liu, Rui-Hua,Yu, Wei,Han, Bing
, p. 3255 - 3258 (2017/06/23)
A novel and facile approach to vicinal oxycyanation and aminocyanation of internal unactivated alkenes is developed. This method utilizes the dichotomous reactivity of iminoxyl radical derived from the initiation of β,γ- and γ,δ-unsaturated ketoximes to provide the general difunctionalization of internal alkenes using tert-butyl hydroperoxide (TBHP) as the environmentally friendly oxidant, CuCN as the commercially available cyanating reagent, and pentamethyldiethylenetriamine (PMDETA) as the ligand. By using this protocol, a series of useful cyano-featured isoxazolines and cyclic nitrones were efficiently prepared.
Green organocatalytic synthesis of isoxazolines via a one-pot oxidation of allyloximes
Triandafillidi, Ierasia,Kokotos, Christoforos G.
, p. 106 - 109 (2017/11/27)
A green, sustainable, organocatalytic, and efficient synthesis of isoxazolines from allyloximes was developed. A 2,2,2-trifluoroacetophenone-catalyzed oxidation of allyloximes, utilizing H2O2 as the green oxidant, was taken advantage of in order to introduce a cheap and environmentally friendly protocol for the synthesis of substituted isoxazolines. A variety of substitution patterns, both aromatic and aliphatic moieties, are well tolerated, leading to isoxazolines in moderate to excellent yields.
Metal-Free Autoxidative Nitrooxylation of Alkenyl Oximes with Molecular Oxygen
Zhang, Xiao-Wei,Xiao, Zu-Feng,Zhuang, Yan-Jun,Wang, Mei-Mei,Kang, Yan-Biao
, p. 1942 - 1945 (2016/07/06)
A metal-free aerobic autoxidative nitrooxylation of alkenyl oximes mediated by tert-butyl nitrite is described. Molecular oxygen is used as the oxidizing reagent, avoiding use of organic trapping reagents such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMP
Transition-metal-free oxychlorination of alkenyl oximes:: In situ generated radicals with tert -butyl nitrite
Zhang, Xiao-Wei,Xiao, Zu-Feng,Wang, Mei-Mei,Zhuang, Yan-Jun,Kang, Yan-Biao
, p. 7275 - 7281 (2016/08/05)
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 be
Oxime-mediated oxychlorination and oxybromination of unactivated olefins
Dong, Kui-Yong,Qin, Hai-Tao,Liu, Feng,Zhu, Chen
, p. 1419 - 1422 (2015/03/04)
An oxime-mediated oxychlorination and oxybromination of unactivated olefins relying on palladium catalysis has been developed. A wide range of chlorinated and brominated isoxazolines has been synthesized in moderate to good yields. To demonstrate the value of the method, the brominated isoxazoline has been further converted to other useful synthetic feedstock.
Iodine(III)-Mediated Oxy-fluorination of Alkenyl Oximes: An Easy Path to Monofluoromethyl-Substituted Isoxazolines
Kong, Weidong,Guo, Quanping,Xu, Zhaoqing,Wang, Guoqiang,Jiang, Xianxing,Wang, Rui
, p. 3686 - 3689 (2015/08/18)
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-fluorinat
Copper-catalyzed oxyazidation of unactivated alkenes: A facile synthesis of isoxazolines featuring an azido substituent
Zhu, Liping,Yu, Hongmei,Xu, Zhaoqing,Jiang, Xianxing,Lin, Li,Wang, Rui
, p. 1562 - 1565 (2014/04/17)
A novel and efficient Cu(OAc)2-catalyzed oxyazidation of unactivated alkenes was developed. The reactions are easy to conduct, occur under mild conditions, and form azido-substituted isoxazolines in good yields.
