2114-03-6Relevant academic research and scientific papers
Electrochemical Oxidative Functionalization of Arylalkynes: Access to α,α-Dibromo Aryl Ketones
Wang, Dan,Wan, Zhaohua,Zhang, Heng,Lei, Aiwen
supporting information, p. 1022 - 1027 (2020/12/31)
A general and effective protocol to synthesize α,α-dibromo aryl ketones has been developed via an electrochemical oxidative method. The reaction proceeds smoothly at room temperature in an undivided cell without the addition of external oxidants. In the reaction process, LiBr acts as both bromine source and supporting electrolyte. This electrooxidation strategy has good substrate applicability and functional group compatibility. Moreover, the reaction could be scaled up efficiently in a continuous flow cell. The target product could undergo further functionalization for the synthesis of some useful heterocyclic compounds. (Figure presented.).
Visible-light-promoted oxidative halogenation of alkynes
Li, Yiming,Mou, Tao,Lu, Lingling,Jiang, Xuefeng
supporting information, p. 14299 - 14302 (2019/12/02)
In nature, halogenation promotes the biological activity of secondary metabolites, especially geminal dihalogenation. Related natural molecules have been studied for decades. In recent years, their diversified vital activities have been explored for treating various diseases, which call for efficient and divergent synthetic strategies to facilitate drug discovery. Here we report a catalyst-free oxidative halogenation achieved under ambient conditions (halide ion, air, water, visible light, room temperature, and normal pressure). Constitutionally, electron transfer between the oxygen and halide ion is shuttled via simple conjugated molecules, in which phenylacetylene works as both reactant and catalyst. Synthetically, it provides a highly compatible late-stage transformation strategy to build up dihaloacetophenones (DHAPs).
Highly efficient recyclable sol gel polymer catalyzed one pot difunctionalization of alkynes
Domena, Justin,Chong, Carlos,Johnson, Qiaxian R.,Chauhan, Bhanu P. S.,Xing, Yalan
supporting information, (2018/08/17)
Amino-bridged gel polymer P1 was discovered to catalyze alkyne halo-functionalization in excellent yields, regioselectivity, functional group compatibility, and recyclability. We have observed that both aromatic and aliphatic alkynes can be converted to α,α-dihalogenated ketones in the presence of polymer P1 under metal-free conditions at room temperature within a short reaction time.
Water-controlled selective preparation of α-mono or α,α′-dihalo ketones: Via catalytic cascade reaction of unactivated alkynes with 1,3-dihalo-5,5-dimethylhydantoin
Wu, Chao,Xin, Xiu,Fu, Zhi-Min,Xie, Long-Yong,Liu, Kai-Jian,Wang, Zheng,Li, Wenyi,Yuan, Zhi-Hui,He, Wei-Min
, p. 1983 - 1989 (2017/06/09)
The control of a reaction that can produce multiple products from the same starting material is a highly attractive and challenging concept in organic synthesis. An efficient protocol for the selective synthesis of α-mono or α,α′-dihalo ketones via a water-controlled three-component thiourea-catalyzed cascade reaction of unactivated alkynes, 1,3-dihalo-5,5-dimethylhydantoin and water has been developed. α-Monohaloketones were obtained in aqueous acetone at 45 °C; conversely, α,α′-dihalo ketones were formed with pure water as the sole solvent at room temperature.
Enantioselective intermolecular all-carbon [4+2] annulation: Via N-heterocyclic carbene organocatalysis
Zhang, Guoxiang,Xu, Weici,Liu, Jian,Das, Deb Kumar,Yang, Shuang,Perveen, Saima,Zhang, Hao,Li, Xinglong,Fang, Xinqiang
supporting information, p. 13336 - 13339 (2017/12/26)
The highly stereoselective intermolecular all-carbon [4+2] annulation between in situ generated acyclic dienolates and α,β-unsaturated acyl azoliums is disclosed. The identification of 2-acyloxy-3-butenones as suitable diene precursors is the key to the s
One-step for the preparation of α-haloacetal of ketones with N-bromosuccinimide/N-chlorosuccinimide (NBS/NCS) and ethylene glycol
Zheng, Zubiao,Han, Bingbing,Wu, Fang,Shi, Tengfei,Liu, Jie,Zhang, Yong,Hao, Jialong
, p. 7738 - 7743 (2016/11/17)
A new process that could directly prepare α-haloacetal of ketones from various ketones with N-halosuccinimide (NBS/NCS) and ethylene glycol in one step without any other catalysts was reported. The effects of solvents, NBS/NCS and reaction temperature were investigated. Under the optimal condition, most of α-haloacetals of ketones were obtained in 90–100% yield.
A versatile and one-pot strategy to synthesize ?±-amino ketones from benzylic secondary alcohols using N -bromosuccinimide
Guha, Somraj,Rajeshkumar, Venkatachalam,Kotha, Surya Srinivas,Sekar, Govindasamy
, p. 406 - 409 (2015/03/04)
A metal-free one-pot strategy has been developed for the first time to synthesize pharmaceutically important ?±-amino ketones from readily available benzylic secondary alcohols and amines using N-bromosuccinimide. This new reaction proceeds via three consecutive steps involving oxidation of alcohols, ?±-bromination of ketones, and nucleophilic substitution of ?±-bromo ketones to give ?±-amino ketones. Importantly, this novel one-pot greener reaction avoids direct usage of toxic and corrosive bromine. This methodology has been employed efficiently to synthesize pharmaceutically important amfepramone and pyrovalerone in a single step.
K 2S 2O 8-mediated difunctionalization of C≡C bonds in water: A simple and efficient approach to α, α -dihaloacetophenones from phenylacetylenes and NaX
Wang, Jing-Yu,Jiang, Qing,Guo, Can-Cheng
supporting information, p. 3130 - 3138 (2015/10/12)
A novel K2S2O8-mediated oxy-1,1-dihalogenation of alkynes with NaX in the presence of water has been developed, affording α,α-dihaloacetophenones in moderate to good yields. The advantages of this reaction are mild reaction conditions, operational simplicity, and use of pure water as reaction medium. A plausible reaction mechanism is proposed on the basis of mechanistic studies.
Halocarbocyclization versus dihalogenation: Substituent directed iodine(iii) catalyzed halogenations
Stodulski, Maciej,Goetzinger, Alissa,Kohlhepp, Stefanie V.,Gulder, Tanja
supporting information, p. 3435 - 3438 (2014/03/21)
The nucleophilicity of the substituents in iodobenzene pre-catalysts have a huge impact on product selectivity in iodine(iii) triggered halogenations, steering the reactivity from solely carbocyclizations towards dihalogenations. Utilizing this catalyst-dependent reactivity a diastereo- and chemoselective dihalogenation method was established allowing the conversion of structurally and electronically diverse unsaturated compounds in excellent yields.
Silica gel catalyzed α-bromination of ketones using N-bromosuccinimide: An easy and rapid method
Mohan Reddy, Bodireddy,Venkata Ramana Kumar, Velpula,Chinna Gangi Reddy, Nallagondu,Mahender Rao, Siripragada
, p. 179 - 182 (2014/02/14)
An easy and rapid method for the α-bromination of ketones using N-bromosuccinimide (NBS) catalyzed by silica gel in methanol under reflux conditions was developed. The expected products were formed in excellent isolated yields within a short period of time (5-20 min). Major advantages of the present procedure include use of inexpensive and readily available catalyst, exclusion of pre- and post-chemical treatment of catalyst and use of methanol as solvent instead of ethers and chlorinated solvents.
