59239-04-2Relevant academic research and scientific papers
Diastereoselective and Stereodivergent Synthesis of 2-Cinnamylpyrrolines Enabled by Photoredox-Catalyzed Iminoalkenylation of Alkenes
Shen, Xu,Huang, Congcong,Yuan, Xiang-Ai,Yu, Shouyun
supporting information, p. 9672 - 9679 (2021/03/16)
A photoredox-catalyzed iminoalkenylation of γ-alkenyl O-acyl oximes has been developed. Readily available alkenylboronic acids serve as alkenylation reagents, leading to densely functionalized pyrrolines. Both (E)- and (Z)-cinnamylpyrrolines are accessible depending on the reaction solvent. In dichloromethane, (E)-cinnamylpyrrolines are produced through a photoredox-mediated single-electron-transfer process. In tetrahydrofuran, (Z)-cinnamylpyrrolines are generated by photocatalytic contra-thermodynamic E-to-Z isomerization of (E)-cinnamylpyrrolines though an energy-transfer pathway. Two stereocenters are established with complete diastereoselectivity and only one diastereomer is isolated.
Dehydrative Beckmann rearrangement and the following cascade reactions
Liu, Yinghui,Wei, Yongjiao,Xie, Lan-Gui
supporting information, (2021/11/16)
The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam. By strategically using the in situ generated Appel's salt or Mitsunobu's zwitterionic adduct as the dehydrating agent, a series of Beckmann rearrangement and following cascade reactions have been developed herein. The protocol allows the conversion of various ketoximes into amide, thioamide, tetrazole and imide products in modular procedures. The generality and tolerance of functionalities of this method have been demonstrated.
Synthesis of 5-Vinyl-2-isoxazolines by Palladium-Catalyzed Intramolecular O-Allylation of Ketoximes
Fernandes, Rodney A.,Gangani, Ashvin J.,Panja, Arpita
supporting information, p. 6227 - 6231 (2021/08/18)
An efficient method for the synthesis of 5-vinyl-2-isoxazolines by Pd-catalyzed intramolecular O-allylation of ketoximes has been developed. The reaction involves Pd(0)-catalyzed π-allyl formation via leaving group ionization or Pd(II)-catalyzed allylic C-H activation followed by intramolecular nucleophilic oxime oxygen attack. This methodology has been elaborated to various value-added products by epoxidation, Wacker oxidation, cross-metathesis, hydroboration-oxidation, dihydroxylation, and catalytic hydrogenation.
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.
Asymmetric Nitrone Synthesis via Ligand-Enabled Copper-Catalyzed Cope-Type Hydroamination of Cyclopropene with Oxime
Li, Zhanyu,Zhao, Jinbo,Sun, Baozhen,Zhou, Tingting,Liu, Mingzhu,Liu, Shuang,Zhang, Mengru,Zhang, Qian
supporting information, p. 11702 - 11705 (2017/09/07)
We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetric cyclopropene "hydronitronylation" process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic studies corroborate a CuI-catalytic profile featuring an olefin metalla-retro-Cope aminocupration process as the key C-N bond forming event. This conceptually novel reactivity enables the first example of highly enantioselective catalytic nitrone formation process and will likely spur further developments that may significantly expedite chiral nitrone synthesis.
Green organocatalytic synthesis of isoxazolines via a one-pot oxidation of allyloximes
Triandafillidi, Ierasia,Kokotos, Christoforos G.
supporting information, 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.
