27570-08-7Relevant articles and documents
Preparation and properties of high birefringence phenylacetylene isothiocyanato-based blend liquid crystals
He, Zemin,Wang, Haiyang,Zhang, Huimin,Zhang, Yongming,Zhao, Yang,Zhao, Yuzhen
, (2022/04/03)
A series of compounds of with high birefringence containing alkoxy–phenylacetylene–isothiocyanato structure were synthesized and characterized. The chemical structures of these compounds were confirmed by FT-IR and 1H-NMR, and transition temperatures and birefringence were measured. One of these compounds with good liquid crystal property and high birefringence was mixed with host liquid crystal to form blend liquid crystal. The effects of the concentration of the compound on phase temperature range, birefringence, resistivity, dielectric anisotropy and photoelectric properties were discussed. The results showed that blend liquid crystal (with 7 wt% compound) exhibited excellent comprehensive performance.
Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
supporting information, p. 6067 - 6072 (2021/08/16)
The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
Illuminatinganti-hydrozirconation: controlled geometric isomerization of an organometallic species
Gilmour, Ryan,Hostmann, Theresa,Nevesely, Tomá?
, p. 10643 - 10648 (2021/08/20)
A general strategy to enable the formalanti-hydrozirconation of arylacetylenes is reported that mergescis-hydrometallation using the Schwartz Reagent (Cp2ZrHCl) with a subsequent light-mediated geometric isomerization atλ= 400 nm. Mechanistic delineation of thecontra-thermodynamic isomerization step indicates that a minor reaction product functions as an efficientin situgenerated photocatalyst. Coupling of theE-vinyl zirconium species with an alkyne unit generates a conjugated diene: this has been leveraged as a selective energy transfer catalyst to enableE→Zisomerization of an organometallic species. Through anUmpolungmetal-halogen exchange process (Cl, Br, I), synthetically useful vinyl halides can be generated (up toZ?:?E= 90?:?10). This enabling platform provides a strategy to access nucleophilic and electrophilic alkene fragments in both geometric forms from simple arylacetylenes.
Cyclic Diaryl λ3-Bromanes: A Rapid Access to Molecular Complexity via Cycloaddition Reactions
Lanzi, Matteo,Ali Abdine, Racha Abed,De Abreu, Maxime,Wencel-Delord, Joanna
supporting information, p. 9047 - 9052 (2021/12/06)
Biaryls have widespread applications in organic synthesis. However, sequentially polysubstituted biaryls are underdeveloped due to their challenging preparation. Herein, we report the synthesis of dissymetric 2,3,2′,3′,4-substituted biaryls via pericyclic reactions of cyclic diaryl λ3-bromanes. The functional groups tolerance and atom economy allow access to molecular complexity in a single reaction step. Continuous flow protocol has been designed for the scale-up of the reaction, while postfunctionalizations have been developed taking advantage of the residual Br-atom.
Alkenylation and Arylation of Peptides via Ni-Catalyzed Reductive Coupling of α- C-Tosyl Peptides with Csp2Triflates/Halides
Chen, Yunrong,Gong, Hegui,Ma, Guobin,Qian, Qun,Song, Yanhong,Sun, Deli,Tao, Xianghua
supporting information, p. 7418 - 7422 (2021/10/12)
A Ni-catalyzed reductive cross-coupling between α-C-tosyl peptides and Csp2 triflates/halides has been developed. This protocol enables the formation of various unnatural di- and tripeptides containing vinyl and aryl side chains, and it expands the applications of Ni-catalyzed reductive cross-coupling in late-stage diversification of peptides.
Iron-Catalyzed Regioselective Alkenylboration of Olefins
Yu, Xiaolong,Zheng, Hongling,Zhao, Haonan,Lee, Boon Chong,Koh, Ming Joo
supporting information, p. 2104 - 2109 (2020/11/30)
The first examples of an iron-catalyzed three-component synthesis of homoallylic boronates from regioselective union of bis(pinacolato)diboron, an alkenyl halide (bromide, chloride or fluoride), and an olefin are disclosed. Products that bear tertiary or quaternary carbon centers could be generated in up to 87 % yield as single regioisomers with complete retention of the olefin stereochemistry. With cyclopropylidene-containing substrates, ring cleavage leading to trisubstituted E-alkenylboronates were selectively obtained. Mechanistic studies revealed reaction attributes that are distinct from previously reported alkene carboboration pathways.
The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
, (2019/12/05)
Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
Iron-Catalyzed Reductive Vinylation of Tertiary Alkyl Oxalates with Activated Vinyl Halides
Chen, Haifeng,Gong, Hegui,Yao, Ken,Ye, Yang
, (2020/03/13)
We present herein a rare and efficient method for the creation of vinylated all carbon quaternary centers via Fe-catalyzed cross-electrophile coupling of vinyl halides with tertiary alkyl methyl oxalates. The reaction displays excellent functional group tolerance and broad substrate scope, which allows cascade radical cyclization and vinylation to afford complex bicyclic and spiral structural motifs. The reaction proceeds via tertiary alkyl radicals, and the putative vinyl-Br/Fe complexation appears to be crucial for activating the alkene and enabling a possibly concerted radical addition/C-Fe forming process.
Photocatalytic Isomerization of Styrenyl Halides: Stereodivergent Synthesis of Functionalized Alkenes
Zhang, Hao,Xu, Qing,Yu, Lei,Yu, Shouyun
supporting information, p. 1472 - 1477 (2019/11/03)
An efficient and general method for the isomerization of styrenyl halides under different photocatalytic conditions (fac-Ir(ppy)3 in methanol for E to Z isomerization and fluorescein in 1,4-dioxane for Z to E isomerization, respectively) is disclosed. A series of stereospecific transformations constitute preliminary validation of this strategy in the synthesis of functionalized alkenes, including two diaryl alkenes, a styrenyl boronic ester and an enyne. The photocatalytic isomerization and subsequent cross coupling reaction can be run in a one-pot manner. The stereodivergent synthesis of all four isomers of a conjugated diene, as well as the antitumor agent DMU-212 and its (Z)-isomer highlights the synthetic applicability of this method.
A Simplified Protocol for the Stereospecific Nickel-Catalyzed C-S Vinylation Using NiX 2 Salts and Alkyl Phosphites
Larin, Egor M.,Lautens, Mark,Marchese, Austin D.,Mirabi, Bijan
, p. 311 - 319 (2019/12/28)
A Ni-catalyzed C-S cross-coupling using only NiI 2 (0.5-2.5 molpercent) and P(O i Pr) 3 (2.0-10.0 molpercent) is reported. Using an air-stable Ni(II) precatalyst, and a cheap and commercially available ligand, a scalable and robust method was developed to cross-couple various thiophenols and styryl bromides, including some sterically encumbered thiols, an α-bromocinnamaldehyde as well as a thiolation-cyclization.
