852058-12-9Relevant academic research and scientific papers
An Umpolung Approach to Alkene Carboamination: Palladium Catalyzed 1,2-Amino-Acylation, -Carboxylation, -Arylation, -Vinylation, and -Alkynylation
Faulkner, Adele,Scott, James S.,Bower, John F.
, p. 7224 - 7230 (2015)
Conventional approaches to Pd-catalyzed alkene 1,2-carboamination rely upon the combination of a nucleophilic nitrogen-based component and an internal C-based or external oxidant. In this study, we outline an umpolung approach, which is triggered by oxidative initiation at an electrophilic N-based component and employs "standard" organometallic nucleophiles to introduce the new carbon-based fragment. Specifically, oxidative addition of a Pd(0)-catalyst into the N-O bond of O-pentafluorobenzoyl oxime esters generates imino-Pd(II) intermediates, which undergo 5-exo cyclization with sterically diverse alkenes. The resultant alkyl-Pd(II) intermediates are intercepted by organometallic nucleophiles or alcohols, under carbonylative or noncarbonylative conditions, to provide 1,2-carboamination products. This approach provides, for the first time, a unified strategy for achieving alkene 1,2-amino-acylation, -carboxylation, -arylation, -vinylation, and -alkynylation. For carbonylative processes, orchestrated protodecarboxylation of the pentafluorobenzoate leaving group underpins reaction efficiency. This process is likely a key feature in related Narasaka-Heck cyclizations and accounts for the efficacy of O-pentafluorobenzoyl oxime esters in aza-Heck reactions of this type. (Chemical Equation Presented).
Highly Enantioselective Construction of Dihydrooxazines via Pd-Catalyzed Asymmetric Carboetherification
Li, Na,Sun, Baozhen,Liu, Shuang,Zhao, Jinbo,Zhang, Qian
supporting information, p. 190 - 193 (2020/01/02)
A straightforward synthesis of highly enantioenriched 5,6-dihydro-4H-1,2-oxazines is realized by Pd-catalyzed asymmetric carboetherification of γ,δ-alkenyl oximes with (hetero)aryl and alkenyl halides in the presence of a commercially available bisphosphine ligand. The enantioenriched products can be facilely converted to functionalized alcohols with high fidelity of chiral transfer.
Iron-catalyzed carbonylative cyclization of γ,δ-unsaturated aromatic oxime esters to functionalized pyrrolines
Wang, Hai,Wu, Xiao-Feng,Yin, Zhiping,Zhang, Youcan
supporting information, p. 7045 - 7048 (2020/07/14)
Herein, a new method of iron-catalyzed carbonylative cyclization of γ,δ-unsaturated aromatic oxime esters to functionalized pyrrolines has been developed. By using readily available substrates, 32 examples of functionalized pyrrolines were prepared in moderate to good yields. Notably, examples of reduction and cycloaddition reactions of the obtained product were given as well. This journal is
Additive-free radical cascade reaction of oxime esters: Synthesis of pyrroline-functionalized phenanthridines
Shao, Liming,Xue, Yijie,Xue, Dengqi,He, Qian,Ge, Qianwei,Li, Wei
, p. 12284 - 12293 (2020/11/10)
A variety of dihydropyrrole-functionalized phenanthridines were efficiently synthesized by the metal-free, radical cascade cyclization reaction of 2-isocyanobiphenyls with γ,δ- unsaturated oxime esters. The C-N/C-C/C-C bonds were formed via the oil bath method in a one-pot procedure with broad substrate applicability. The radical process was supported by kinetic isotope effect studies and radical inhibition studies.
Copper-Catalyzed Cope-Type Hydroamination of Nonactivated Olefins toward Cyclic Nitrones: Scope, Mechanism, and Enantioselective Process Development
Zhang, Mengru,Liu, Shuang,Li, Hexin,Guo, Yajing,Li, Na,Guan, Meihui,Mehfooz, Haroon,Zhao, Jinbo,Zhang, Qian
supporting information, p. 12620 - 12627 (2019/09/16)
The catalytic synthesis of cyclic nitrones, an important type of functional molecules for both synthetic chemistry and related fields, remains underdeveloped. Herein we report the copper-catalyzed Cope-type hydroamination of oximes with pendant nonactivated olefins, which enables facile access to a series of five- and six-membered cyclic nitrones under mild conditions. In this study, heterocycle-tethered oximes were employed in the Cope-type hydroamination reaction for the first time. High enantioselectivity was achieved for carbon-tethered γ,δ-vinyl oximes to afford enantioenriched five-membered cyclic nitrones. The results of preliminary mechanistic studies indicate a mononuclear catalytic species and a unified catalytic pathway over a large temperature range.
Visible-Light-Mediated Iminyl Radical Generation from Benzyl Oxime Ether: Synthesis of Pyrroline via Hydroimination Cyclization
Usami, Kaoru,Yamaguchi, Eiji,Tada, Norihiro,Itoh, Akichika
supporting information, p. 5714 - 5717 (2018/09/21)
The treatment of an O-(4-methoxybenzyl) oxime ether bearing an olefin substituent and 1-chloroanthraquinone (1-Cl-AQN) catalyst in 2-butanone under visible-light irradiation affords pyrroline via an iminyl radical intramolecular hydroimination. Mechanistic studies indicate that iminyl radical generation mainly proceeds by hydrogen abstraction of the photocatalyst from the benzyl position of the oxime. Moreover, the hydrogen atom was identified in circulation from the benzylic position of the substrates between AQN and 2-butanone to quench the carbon radical without requiring any additional reagents.
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
supporting information, 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.
Iminoxyl radical-promoted dichotomous cyclizations: Efficient oxyoximation and aminooximation of alkenes
Peng, Xie-Xue,Deng, Yun-Jing,Yang, Xiu-Long,Zhang, Lin,Yu, Wei,Han, Bing
supporting information, p. 4650 - 4653 (2015/01/08)
A novel iminoxyl radical-involved metal-free approach to vicinal oxyoximation and aminooximation of unactivated alkenes is developed. This method utilizes the dichotomous reactivity of the iminoxyl radical to furnish a general difunctionalization on alkenes using simple tert-butyl nitrite (TBN) as the iminoxyl radical initiator as well the carbon radical trap. By using this protocol, oxime featured 4,5-dihydroisoxazoles and cyclic nitrones were facilely prepared from β,γ- and γ,δ-unsaturated ketoximes, respectively.
Copper-catalyzed intramolecular oxytrifluoromethylthiolation of unactivated alkenes
Zhu, Liping,Wang, Guoqiang,Guo, Quanping,Xu, Zhaoqing,Zhang, Di,Wang, Rui
supporting information, p. 5390 - 5393 (2015/01/09)
A mild, versatile, and convenient method for efficient intramolecular oxytrifluoromethylthiolation of unactivated alkenes catalyzed by Cu(OAc)2 has been developed. The reactions were carried out under aerobic conditions and formed a variety of isoxazolines bearing a -SCF3 substituent. (Chemical Equation Presented).
Oxime radical promoted dioxygenation, oxyamination, and diamination of alkenes: Synthesis of isoxazolines and cyclic nitrones
Han, Bing,Yang, Xiu-Long,Fang, Ran,Yu, Wei,Wang, Chao,Duan, Xiao-Yong,Liu, Shuai
supporting information; experimental part, p. 8816 - 8820 (2012/10/18)
Up the tempo: The intramolecular addition of oxime radicals to C=C bonds was achieved by using DEAD and TEMPO to give 4,5-dihydroisoxazoles as a result of a C=O bond-forming, 5-exo-trig cyclization. γ,δ-Unsaturated ketoximes also reacted to afford cyclic nitrones through C-N bond formation. The reactions offer a metal-free approach for the vicinal difunctionalization of unactivated alkenes. Copyright
