199188-30-2Relevant academic research and scientific papers
Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
supporting information, p. 6755 - 6764 (2019/05/06)
Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
ortho-Difunctionalization of arynes by LiZnEt2(TMP)-mediated deprotonative zincation/elimination of aryl triflates
Cho, Seoyoung,Wang, Qiu
supporting information, p. 3325 - 3328 (2018/04/02)
Generation of arynes from aryl triflates has been achieved using lithium diethyl(tetramethylpiperidyl)-zincate base LiZnEt2(TMP), via a directed ortho-deprotonative zincation and subsequent elimination of the triflate group. The aryne formation
Barbier–Negishi Coupling of Secondary Alkyl Bromides with Aryl and Alkenyl Triflates and Nonaflates
Zhang, Ke-Feng,Christoffel, Fadri,Baudoin, Olivier
supporting information, p. 1982 - 1986 (2018/02/06)
A mild and practical Barbier–Negishi coupling of secondary alkyl bromides with aryl and alkenyl triflates and nonaflates has been developed. This challenging reaction was enabled by the use of a very bulky imidazole-based phosphine ligand, which resulted in good yields as well as good chemo- and site selectivities for a broad range of substrates at room temperature and under non-aqueous conditions. This reaction was extended to primary alkyl bromides by using an analogous pyrazole-based ligand.
Palladium nanoparticles: Chemoselective control for reductive Heck with aryl triflates and 2,3-dihydrofuran
Rosas Vargas, Daisy,Cook, Silas P.
supporting information, p. 3314 - 3317 (2018/05/04)
The reductive-Heck reaction offers a unique entry to formal Csp2-Csp3 cross-coupling reactions that proceed in the absence of a main group organometallic coupling partner. Consequently, further development of new variants would be transformative. Unfortunately, controlling the relative rates of the organopalladium intermediates has proven difficult with homogenous, single-site Pd catalysts. This work describes a selective reductive Heck reaction catalyzed by Pd-nanoparticles. The reaction works well with electron-deficient aryl triflates at room temperature in the absence of ligands. This work addresses some of the challenges found in the reductive-Heck literature.
Achieving vinylic selectivity in Mizoroki-heck reaction of cyclic olefins
Wu, Xiaojin,Lu, Yunpeng,Hirao, Hajime,Zhou, Jianrong
supporting information, p. 6014 - 6020 (2013/06/26)
In Heck reactions of cyclic olefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclic olefins of various ring size worked well. The desired isomers were produced by palladium-hydride-catalyzed isomerization of the initial products. Thus, a specific catalyst must be used so that it can perform two jobs under one set of reaction conditions. Copyright
Zinc trimethylsilylamide as a mild ammonia equivalent and base for the amination of aryl halides and triflates
Lee, Dae-Yon,Hartwig, John F.
, p. 1169 - 1172 (2007/10/03)
(Chemical Equation Presented) We report that Zn[N(SiMe3) 2]2 is a mild ammonia equivalent and base for the palladium-catalyzed amination of aryl halides and triflates. In contrast to LiN(SiMe3)2, the combination of Zn[N(SiMe 3)2]2 and LiCl coupled with aryl halides and triflates containing base-sensitive functionality in high yields. In addition, aryl bromides coupled with aryl and alkylamines with the combination of Zn[N(SiMe3)2]2 and LiCl as base. These aminations occurred without racemization of the enolizable stereocenter of an optically active ester.
On the preparation of ortho-trifluoromethyl phenyl triflate
Gill, Duncan,Hester, Alison J.,Lloyd-Jones, Guy C.
, p. 2547 - 2548 (2007/10/03)
In contrast to an earlier report advocating a copper-mediated trifluoromethylation of ortho-iodophenyl triflate, ortho-trifluoromethyl phenyl triflate may be prepared simply by reacting the corresponding phenol with triflic anhydride in the presence of a
First synthesis of ortho-trifluoromethylated aryl triflates
Qing, Feng-Ling,Fan, Junfa,Sun, Hong-Bin,Yue, Xiang-Jun
, p. 3053 - 3057 (2007/10/03)
An efficient method for the preparation of trifluoromethylated aryl triflates (trifluoromethanesulfonates) has been developed. Treatment of 2-iodophenol with trifluoromethanesulfonic anhydride in the presence of triethylamine gives triflate 3. Then, reaction of compound 3 with FSO2CF2CO2Me and CuI in DMF-HMPA affords trifluoromethylated aryl triflate 2. This reaction sequence is also successful for meta- and para-trifluoromethylated aryl triflates. Based on this methodology, the trifluoromethylated aryl triflate 11, a key intermediate for the preparation of the conformationally restricted retinoid 8 containing a trifluoromethyl group, has been synthesized. The cross-coupling of aryl triflate 11 with vinylstannane 17 under palladium catalysis provides compound 18, the methyl ester of retinoid 8, in moderate yield.
A Facile Preparation of Aryl Triflates. Decomposition of Arenediazonium Tetrafluoroborate Salts in Trifluoromethanesulfonic Acid
Yoneda, Norihiko,Fukuhara, Tsuyoshi,Mizokami, Takao,Suzuki, Akira
, p. 459 - 460 (2007/10/02)
The thermal or photochemical decomposition of arenediazonium tetrafluoroborate salts n trifluoromethanesulfonic acid, with or without organic bases such as pyridine, provides aryl triflates in high yields.
