72012-52-3Relevant academic research and scientific papers
Photoexcitation of flavoenzymes enables a stereoselective radical cyclization
Biegasiewicz, Kyle F.,Cooper, Simon J.,Gao, Xin,Oblinsky, Daniel G.,Kim, Ji Hye,Garfinkle, Samuel E.,Joyce, Leo A.,Sandoval, Braddock A.,Scholes, Gregory D.,Hyster, Todd K.
, p. 1166 - 1169 (2019)
Photoexcitation is a common strategy for initiating radical reactions in chemical synthesis. We found that photoexcitation of flavin-dependent “ene”-reductases changes their catalytic function, enabling these enzymes to promote an asymmetric radical cycli
Synthesis of Terminal N-Vinylazoles from Aromatic Aldehydes, DMSO, and Azoles Based DMSO as Terminal Carbon Synthon
Nie, Zhiwen,Lv, Huifang,Li, Hui,Su, Miaodong,Yang, Tonglin,Luo, Weiping,Liu, Qiang,Guo, Cancheng
, p. 4621 - 4626 (2021/09/02)
A protocol for the synthesis of terminal N-vinylazoles from aromatic aldehydes, DMSO, and azoles has been reported. In this strategy, DMSO was involved in the construction of the C=C bond as a terminal carbon synthon. Both aromatic aldehydes and azoles could be well tolerated and give the corresponding terminal N-vinylazoles in 52–91% yields. Based on preliminary experiments, a plausible mechanism is proposed. (Figure presented.).
Rhodium(III)-Catalyzed Direct C-H Arylation of Various Acyclic Enamides with Arylsilanes
Li, Xiaolan,Sun, Kai,Shen, Wenjuan,Zhang, Yong,Lu, Ming-Zhu,Luo, Xuzhong,Luo, Haiqing
supporting information, p. 31 - 36 (2021/01/09)
The stereoselective β-C(sp2)-H arylation of various acyclic enamides with arylsilanes via Rh(III)-catalyzed cross-coupling reaction was illustrated. The methodology was characterized by extraordinary efficacy and stereoselectivity, a wide scope of substrates, good functional group tolerance, and the adoption of environmentally friendly arylsilanes. The utility of this present method was evidenced by the gram-scale synthesis and further elaboration of the product. In addition, Rh(III)-catalyzed C-H activation is considered to be the critical step in the reaction mechanism.
Visible-light-promoted olefinic trifluoromethylation of enamides with CF3SO2Na
Chen, Kai,Chen, Yixuan,Guan, Jianping,Tang, Kai,Wang, Zhujun,Xiang, Haoyue,Yang, Hua
, p. 7475 - 7479 (2021/09/08)
A visible-light-promoted olefinic C-H trifluoromethylation of enamides was developed by employing cheap and stable Langlois’ reagent as the CF3source. A series of β-CF3enamides were obtained in moderate to good yields with highE-isomer selectivity under mild conditions. Preliminary mechanistic studies suggest that molecular oxygen acts as the terminal oxidant for this net oxidative process, and theEisomer selectivity could be well explained by a base-assisted deprotonation of the cation intermediate.
Synthesis of Functionalized Vinylsilanes via Metal-Free Dehydrogenative Silylation of Enamides
Chang, Xi-Hao,Wang, Zi-Lu,Zhao, Meng,Yang, Chao,Li, Jie-Jun,Ma, Wei-Wei,Xu, Yun-He
, p. 1326 - 1330 (2020/02/13)
A novel method of metal-free dehydrogenative silylation of enamides has been developed. The desired functionalized vinylsilane products were obtained in moderate to good yield and with high stereoselectivities. This protocol displays good tolerance of various functionalities. Furthermore, the high chemoselectivity of this reaction enables us to introduce different unsaturated C-C moieties to the products. The ease of further derivatization of the products to other useful compounds also demonstrates the highly synthetic utility of the current methodology.
C(sp2)-H Trifluoromethylation of enamides using TMSCF3: Access to trifluoromethylated isoindolinones, isoquinolinones, 2-pyridinones and other heterocycles
Krishnamurti, Vinayak,Munoz, Socrates B.,Ispizua-Rodriguez, Xanath,Vickerman, Jeffrey,Mathew, Thomas,Surya Prakash
, p. 10574 - 10577 (2018/09/27)
A method for the direct C(sp2)-H trifluoromethylation of enamides, including biologically relevant isoindolinones, isoquinolinones and 2-pyridinones using TMSCF3 under oxidative conditions is presented. The protocol is convenient, operationally simple and exhibits high tolerance across a multitude of relevant handles and functional groups.
Amide-assisted acetoxylation of vinyl C(sp2)-H bonds by rhodium catalysis
Yu, Wenlong,Chen, Jia,Gao, Kun,Liu, Zhanxiang,Zhang, Yuhong
supporting information, p. 4870 - 4873 (2015/04/27)
A direct regioselective acetoxylation of enamides has been accomplished using a combination of Cu(OAc)2 and rhodium catalyst. Cu(OAc)2 is served as the oxidant and also provides the source of acetate in the reaction.
Hydrogen-bond-directed catalysis: Faster, regioselective and cleaner heck arylation of electron-rich olefins in alcohols
Hyder, Zeynab,Ruan, Jiwu,Xiao, Jianliang
experimental part, p. 5555 - 5566 (2009/06/17)
A general method for the regioselective Heck reaction of electronrich olefins is presented. Fast, highly regioselective Pd-catalysed α-arylation of electron-rich olefins, vinyl ethers (1a-d), hydroxyl vinyl ethers (1e,f), enamides (1g,h) and a substituted vinyl ether (1i) has been accomplished with a diverse range of aryl bromides (2a-r), for the first time, in cheap, green and easily available alcohols with no need for any halide scavengers or salt additives. The reaction proceeds with high efficiency, leading exclusively to the a-products, in 2-propanol and particularly in ethylene glycol. In the latter, the arylation can be catalysed at a palladium loading of 0.1 mol% and finish in as short a time as 0.5 h. The remarkable performance of the alcohol solvents in promoting a regiocontrol is attributed to their hydrogen-bond- donating capability, which is believed to facilitate the dissociation of halide anions from PdII, and hence, the generation of a key ionic Pd II-olefin intermediate responsible for the a product. This belief is further strengthened by the study of a benchmark arylation reaction in 21 different solvents. The study revealed that exclusive α-regioselective arylation takes place in almost all of the protic solvents, and there is a rough correlation between the α-arylation rates and the solvent parameter ETN. The method is simpler, cleaner and more general than those established thus far.
PALLADIUM CATALYSED HECK ARYLATION OR VINYLATION OF 1-SUBSTITUTED OLEFINS
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Page/Page column 14; 17; 20, (2008/06/13)
The present invention relates to a process for preparing arylated or vinylated olefins.
The Heck reaction of electron-rich olefins with regiocontrol by hydrogen-bond donors
Mo, Jun,Xiao, Jianliang
, p. 4152 - 4157 (2007/10/03)
No salt please: Halide scavengers AgOTf and TlOAc are not required for the Heck coupling of electron-rich olefins with aryl bromides and chlorides. Using ammonium additives, these reactions can be carried out in either an imidazolium ionic liquid or a common molecular solvent, thus furnishing 1,1′- disubstituted olefins in high yields with excellent regioselectivities. (Chemical Equation Presented).
