149777-81-1Relevant articles and documents
Creating High Regioselectivity by Electronic Metal-Support Interaction of a Single-Atomic-Site Catalyst
Jing, Hongyu,Li, Jiong,Li, Wen-Hao,Li, Yadong,Wang, Dingsheng,Wang, Yu,Yang, Jiarui,Zhang, Jian,Zhao, Jie
supporting information, p. 15453 - 15461 (2021/09/30)
Ligands are the most commonly used means to control the regioselectivity of organic reactions. It is very important to develop new regioselective control methods for organic synthesis. In this study, we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal-support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation to the alkyne on the metal catalytic intermediate was enhanced during the reaction by using transient electron-rich characteristics. In this way, the reaction achieved highly linear-E-type regioselective conversion of electronically unbiased alkynes and completely avoided the formation of branched isomers (ln:br >100:1, TON up to 612, 3 times higher than previously recorded). The structural elements of the SACs were designed following the requirements of the synthesis mechanism. Every element in the catalyst played an important role in the synthesis mechanism. This demonstrated that the EMSI, which is normally thought to be responsible for the improvement in catalytic efficiency and durability in heterogeneous catalysis, now first shows exciting potential for regulating the regioselectivity in homogeneous catalysis.
Electrochemical Hydroboration of Alkynes
Aelterman, Maude,Jubault, Philippe,Poisson, Thomas,Sayes, Morgane
supporting information, p. 8277 - 8282 (2021/05/27)
Herein we reported the electrochemical hydroboration of alkynes by using B2Pin2 as the boron source. This unprecedented reaction manifold was applied to a broad range of alkynes, giving the hydroboration products in good to excellent yields without the need of a metal catalyst or a hydride source. This transformation relied on the possible electrochemical oxidation of an in situ formed borate. This anodic oxidation performed in an undivided cell allowed the formation of a putative boryl radical, which reacted on the alkyne.
Cs4B4O3F10: First Fluorooxoborate with [BF4] Involving Heteroanionic Units and Extremely Low Melting Point
Xia, Ming,Mutailipu, Miriding,Li, Fuming,Yang, Zhihua,Pan, Shilie
supporting information, p. 9753 - 9757 (2021/05/27)
Herein, a new congruently melting mixed-anion compound Cs4B4O3F10 has been characterized as the first fluorooxoborate with [BF4] involving heteroanionic units. Compound Cs4B4O3F10 possesses two highly fluorinated anionic clusters and therefore its formula can be expressed as Cs3(B3O3F6) ? Cs(BF4). The influence of [BF4] units on micro-symmetry and structural evolution was discussed based on the parent compound. More importantly, Cs4B4O3F10 shows the lowest melting point among all the available borates and thus sets a new record for such system. This work is of great significance to enrich and tailor the structure of borates using perfluorinated [BF4] units.
Rhodium-Catalyzed Deoxygenation and Borylation of Ketones: A Combined Experimental and Theoretical Investigation
Tao, Lei,Guo, Xueying,Li, Jie,Li, Ruoling,Lin, Zhenyang,Zhao, Wanxiang
supporting information, p. 18118 - 18127 (2020/11/26)
The rhodium-catalyzed deoxygenation and borylation of ketones with B2pin2 have been developed, leading to efficient formation of alkenes, vinylboronates, and vinyldiboronates. These reactions feature mild reaction conditions, a broad substrate scope, and excellent functional-group compatibility. Mechanistic studies support that the ketones initially undergo a Rh-catalyzed deoxygenation to give alkenes via boron enolate intermediates, and the subsequent Rh-catalyzed dehydrogenative borylation of alkenes leads to the formation of vinylboronates and diboration products, which is also supported by density functional theory calculations.
Direct Synthesis of Alkenylboronates from Alkenes and Pinacol Diboron via Copper Catalysis
Lu, Wenkui,Shen, Zengming
supporting information, p. 142 - 146 (2019/01/11)
We report an efficient approach for the direct synthesis of alkenylboronates using copper catalysis. The Cu/TEMPO catalyst system (where TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) exhibits both excellent reactivity and selectivity for the synthesis of alkenylboronates, starting from inexpensive and abundant alkenes and pinacol diboron. This approach allows for the direct functionalization of both aromatic and aliphatic terminal alkenes. Mechanistic experiments suggest that the alkenylboronates arise from oxyboration intermediates.
AgSbF6-Catalyzed: Anti -Markovnikov hydroboration of terminal alkynes
Mamidala, Ramesh,Pandey, Vipin K.,Rit, Arnab
supporting information, p. 989 - 992 (2019/01/23)
AgSbF6-Catalyzed anti-Markovnikov addition of pinacolborane (HBpin) to terminal alkynes to produce the E-vinylboronates is reported. This efficient methodology is scalable, compatible with sterically and electronically diverse alkynes, and works at room temperature under solvent-free condition. The utility of this method is demonstrated in the facile synthesis of the clinically important (E)-2,4,3′,5′-tetramethoxystilbene.
Transition-Metal-Free Deaminative Vinylation of Alkylamines
Hu, Jiefeng,Cheng, Bo,Yang, Xianyu,Loh, Teck-Peng
supporting information, p. 4902 - 4908 (2019/09/13)
The amino group is one of the most fundamental structural motifs in natural products and synthetic chemicals. However, amines potential as effective alkylating agents in organic synthesis is still problematic. A unified strategy has been established for deaminative vinylation of the alkylamines with vinyl boronic acids by C?N bond activation under catalyst-free conditions. The key to the high reactivity is the utilization of pyridinium salt-activated alkylamines, with a base as a promoter. The transformation exhibits good functional group compatibility, and includes inexpensive primary amine feedstocks and amino acids. The proposed method can serve as a powerful synthetic method for late-stage modification of complex compounds. Mechanistic experiments suggest that free radical processes are involved in this system. (Figure presented.).
Selective and efficient synthesis of trans-arylvinylboronates and trans-hetarylvinylboronates using palladium catalyzed cross-coupling
Liu, Zhihao,Wei, Wei,Xiong, Lu,Feng, Qiang,Shi, Yaojie,Wang, Ningyu,Yu, Luoting
supporting information, p. 3172 - 3176 (2017/04/14)
trans-Arylvinylboronate derivatives are important synthesis blocks in natural products, pharmaceuticals and organic materials. There are only a few reaction conditions that could selectively provide trans-arylvinylboronates by Heck coupling of pinacol vin
Cyclodextrin Cavity-Induced Mechanistic Switch in Copper-Catalyzed Hydroboration
Zhang, Pinglu,Meijide Suárez, Jorge,Driant, Thomas,Derat, Etienne,Zhang, Yongmin,Ménand, Micka?l,Roland, Sylvain,Sollogoub, Matthieu
supporting information, p. 10821 - 10825 (2017/08/30)
N-heterocyclic carbene-capped cyclodextrin (ICyD) ligands, α-ICyD and β-ICyD derived from α- and β-cyclodextrin, respectively give opposite regioselectivities in a copper-catalyzed hydroboration. The site-selectivity results from two different mechanisms: the conventional parallel one and a new orthogonal mechanism. The shape of the cavity was shown not only to induce a regioselectivity switch but also a mechanistic switch. The scope of interest of the encapsulation of a reactive center is therefore broadened by this study.
(CAAC)CuX-catalyzed hydroboration of terminal alkynes with pinacolborane directed by the X-ligand
Romero, Erik A.,Jazzar, Rodolphe,Bertrand, Guy
supporting information, p. 11 - 13 (2017/02/18)
When X is a basic ligand (CAAC)CuX complexes [CAAC?=?cyclic (alkyl) (amino)carbene] selectively promote the (E)-β-hydroboration of terminal alkynes with pinacolborane instead of the dehydrogenative borylation observed with weakly nucleophilic X ligand. This methodology is applicable to a variety of terminal alkynes. Deuterium labeling experiments coupled with stoichiometric reactions give evidence towards a plausible mechanism involving a σ-mono (copper)acetylide complex.
