958633-19-7Relevant academic research and scientific papers
Photocatalyzed E→Z Contra-thermodynamic Isomerization of Vinyl Boronates with Binaphthol
Brégent, Thibaud,Bouillon, Jean-Philippe,Poisson, Thomas
supporting information, p. 13966 - 13970 (2021/08/25)
The photocatalytic contra-thermodynamic E→Z isomerization of vinyl boronates by using a binaphthol catalyst is disclosed. The reaction, based on the transient formation of a suitable chromophore with a BINOL derivative as the catalyst, allowed geometrical isomerization in good-to-excellent Z/E ratio and excellent-to-quantitative yields. The mechanism of this E→Z contra-thermodynamic isomerization was studied, and the formation of a transient chromophore species is suggested.
Stereoselective Synthesis of Trisubstituted Alkenylboron Reagents by Boron-Wittig Reaction of Ketones
Namirembe, Sheila,Gao, Chenpeng,Wexler, Ryan P.,Morken, James P.
supporting information, p. 4392 - 4394 (2019/06/14)
Application of the boron-Wittig reaction to ketone electrophiles provides a straightforward route to trisubstituted alkenylboronic esters. With either a pentamethyldiethylenetriamine or trimethyl-1,4,7-triazacyclononane additive, the olefination can occur
Contra-Thermodynamic, Photocatalytic E→Z Isomerization of Styrenyl Boron Species: Vectors to Facilitate Exploration of Two-Dimensional Chemical Space
Molloy, John J.,Metternich, Jan B.,Daniliuc, Constantin G.,Watson, Allan J. B.,Gilmour, Ryan
supporting information, p. 3168 - 3172 (2018/02/26)
Designing strategies to access stereodefined olefinic organoboron species is an important synthetic challenge. Despite significant advances, there is a striking paucity of routes to Z-α-substituted styrenyl organoborons. Herein, this strategic imbalance is redressed by exploiting the polarity of the C(sp2)?B bond to activate the neighboring π system, thus enabling a mild, traceless photocatalytic isomerization of readily accessible E-α-substituted styrenyl BPins to generate the corresponding Z-isomers with high fidelity. Preliminary validation of this contra-thermodynamic E→Z isomerization is demonstrated in a series of stereoretentive transformations to generate Z-configured trisubstituted alkenes, as well as in a concise synthesis of the anti-tumor agent Combretastatin A4.
Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
supporting information, p. 2897 - 2900 (2016/03/19)
The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
Synthesis of substituted picenes through Pd-catalyzed cross-coupling reaction/annulation sequences and their physicochemical properties
Chang, Ning-Hui,Chen, Xi-Chao,Nonobe, Hikaru,Okuda, Yasuhiro,Mori, Hiroki,Nakajima, Kiyohiko,Nishihara, Yasushi
supporting information, p. 3558 - 3561 (2013/08/23)
A novel and versatile synthetic method for picene derivatives is developed using the Pd-catalyzed intramolecular double cyclization of the corresponding 2,3-bis[(1Z)-2-phenylethenyl]-1,4-dichlorobenzenes, which are readily prepared by Suzuki-Miyaura cross-coupling reactions of polyhalobenzenes with (Z)-arylethenylboronates. The physical properties of the obtained picenes can be modified via introducing a variety of functional groups to the picene framework. All compounds are investigated by UV-vis and fluorescence spectroscopic measurements, CV, and DFT calculations as well as X-ray diffraction analysis.
Iridium-catalyzed enantioselective hydrogenation of alkenylboronic esters
Ganic, Adnan,Pfaltz, Andreas
supporting information; experimental part, p. 6724 - 6728 (2012/07/28)
Choose the right ligand: An iridium complex derived from a phosphino-imidazoline ligand is a highly efficient catalyst for the asymmetric hydrogenation of terminal vinyl boronic esters (see scheme). On the other hand, trisubstituted alkenyl-boronates can
Zirconocene-mediated highly regio- and stereoselective synthesis of multisubstituted olefins starting from 1-alkynylboronates
Nishihara, Yasushi,Miyasaka, Mitsuru,Okamoto, Masanori,Takahashi, Hideki,Inoue, Eiji,Tanemura, Kenki,Takagi, Kentaro
, p. 12634 - 12635 (2008/03/13)
Multisubstituted olefins are efficiently prepared by the zirconocene-mediated regio- and stereoselective coupling between 1-alkynylboronates and ethylene, followed by sequential transformation in moderate to high yields. The proper combination of substrates and reaction conditions is important for high yields. The synthesis of various tetrasubstituted alkenes in a regio- and stereocontrolled manner is described. This methodology has been applied to the synthesis of (Z)-tamoxifen in a concise, regio- and stereoselective manner. This multicomponent coupling strategy involves the characteristics of 1-alkynylboronates toward high selectivities followed by palladium(0)-mediated cross-coupling with aryl halides. Copyright
