83947-56-2Relevant articles and documents
Synthesis of tri-substituted vinyl boronates via ruthenium-catalyzed olefin cross-metathesis
Morrill, Christie,Funk, Timothy W.,Grubbs, Robert H.
, p. 7733 - 7736 (2004)
Tri-substituted vinyl pinacol boronates are synthesized using cross-metathesis of α-substituted vinyl boronates. The reactions proceed with moderate yields and high Z-selectivity when R1 = methyl. When R1 is larger than a methyl group, yields and Z-selectivity are moderate at best, and the reactions are highly substrate dependent.
Neosilyllithium-Catalyzed Hydroboration of Alkynes and Alkenes in the Presence of Pinacolborane (HBpin)
Kumar, Gobbilla Sai,Moorthy, Shruti,Karmakar, Himadri,Singh, Saurabh Kumar,Panda, Tarun K.
supporting information, (2021/11/13)
We report here a novel protocol for the hydroboration of alkynes and alkenes, which in the presence of neosilyllithium (LiCH2SiMe3) (5 mol %) and pinacolborane efficiently results in the formation of corresponding alkenyl and alkyl b
(Z)-Selective Hydroboration of Terminal Alkynes Catalyzed by a PSP-Pincer Rhodium Complex
Lyu, Yanzong,Toriumi, Naoyuki,Iwasawa, Nobuharu
supporting information, p. 9262 - 9266 (2021/11/30)
A highly (Z)-selective hydroboration of terminal alkynes was achieved using a thioxanthene-based PSP-pincer rhodium catalyst. This hydroboration exhibited good chemoselectivity toward alkynes over carbonyl compounds such as ketones and aldehydes. The mechanistic studies indicated the involvement of rhodium-vinylidene intermediates, and the high (Z)-selectivity could be attributed to the rigid and electron-rich nature of the PSP-rhodium catalyst.
Synthesis method of alkenyl boric acid ester
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Paragraph 0022-0025, (2021/05/12)
The invention discloses a synthesis method of alkenyl boric acid ester. The alkenyl boric acid ester compound with a diversified structure is obtained by catalyzing hydroboration of alkyne through rare earth. Particularly, the alkenyl boric acid ester com
Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights Via Experimental and Computational Studies
Mai, Binh Khanh,Nguyen, Thanh Vinh,Ton, Nhan N. H.
supporting information, p. 9117 - 9133 (2021/07/19)
Hydroboration reaction of alkynes is one of the most synthetically powerful tools to access organoboron compounds, versatile precursors for cross-coupling chemistry. This type of reaction has traditionally been mediated by transition-metal or main group catalysts. Herein, we report a novel method using tropylium salts, typically known as organic oxidants and Lewis acids, to promote the hydroboration reaction of alkynes. A broad range of vinylboranes can be easily accessed via this metal-free protocol. Similar hydroboration reactions of alkenes and epoxides can also be efficiently catalyzed by the same tropylium catalysts. Experimental studies and DFT calculations suggested that the reaction follows an uncommon mechanistic pathway, which is triggered by the hydride abstraction of pinacolborane with tropylium ion. This is followed by a series ofin situcounterion-activated substituent exchanges to generate boron intermediates that promote the hydroboration reaction.
Synthesis method of alkenyl borate
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Paragraph 0012; 0023-0027, (2021/10/30)
The invention discloses a synthesis method of alkenyl borate, which comprises the following steps: adding an alkyne substance, pinacolborane and a lithium amide catalyst into a reaction vessel filled with an organic solvent in a nitrogen atmosphere, stirring and mixing, uniformly mixing, reacting at the temperature of 70-110 DEG C for 18-28 hours, filtering and purifying after the reaction is finished to obtain a product, wherein the lithium amide catalyst is lithium bis(trimethylsilyl) amide; the alkyne substance is any one of substances such as phenylacetylene and 4-methyl phenylacetylene. The method is mild in reaction condition, easy to achieve and safe; the target product can be directly synthesized, an intermediate product does not need to be separated, and the highest yield can reach 98%; the catalyst is easy to prepare, and reactant raw materials are easy to obtain; the waste solution in the reaction process is less, other pollution gases and liquids are not discharged, so that the discharge of the waste solution is reduced, and the method has the advantages of protecting the environment and guaranteeing the health of operators.
Aluminum-Hydride-Catalyzed Hydroboration of Carbon Dioxide
Chia, Cher-Chiek,Teo, Yeow-Chuan,Cham, Ning,Ho, Samuel Ying-Fu,Ng, Zhe-Hua,Toh, Hui-Min,Mézailles, Nicolas,So, Cheuk-Wai
supporting information, p. 4569 - 4577 (2021/04/09)
This study describes the first use of a bis(phosphoranyl)methanido aluminum hydride, [ClC(PPh2NMes)2AlH2] (2, Mes = Me3C6H2), for the catalytic hydroboration of CO2. Complex 2 was synthesized by the reaction of a lithium carbenoid [Li(Cl)C(PPh2NMes)2] with 2 equiv of AlH3·NEtMe2 in toluene at -78 °C. 2 (10 mol %) was able to catalyze the reduction of CO2 with HBpin in C6D6 at 110 °C for 2 days to afford a mixture of methoxyborane [MeOBpin] (3a; yield: 78%, TOF: 0.16 h-1) and bis(boryl)oxide [pinBOBpin] (3b). When more potent [BH3·SMe2] was used instead of HBpin, the catalytic reaction was extremely pure, resulting in the formation of trimethyl borate [B(OMe)3] (3e) [catalytic loading: 1 mol % (10 mol %); reaction time: 60 min (5 min); yield: 97.6% (>99%); TOF: 292.8 h-1 (356.4 h-1)] and B2O3 (3f). Mechanistic studies show that the Al-H bond in complex 2 activated CO2 to form [ClC(PPh2NMes)2Al(H){OC(O)H}] (4), which was subsequently reacted with BH3·SMe2 to form 3e and 3f, along with the regeneration of complex 2. Complex 2 also shows good catalytic activity toward the hydroboration of carbonyl, nitrile, and alkyne derivatives.
Zwitterion-Initiated Hydroboration of Alkynes and Styrene
Bismuto, Alessandro,Cowley, Michael J.,Thomas, Stephen P.
supporting information, p. 2382 - 2385 (2021/01/18)
The hydroboration of alkynes and styrene with HBpin has been developed using tris(pentaflurophenyl)borane (B(C6F5)3) as the initiator of catalysis. The hydroboration is proposed to be initiated by Lewis acid activation of the alkyne by (B(C6F5)3) to form a highly reactive zwitterionic species which subsequently react with HBpin to give the alkenyl boronic ester. This zwitterion has also showed potential to be a competent catalyst for the hydroboration of styrene. The zwitterionic intermediate is analogous to that proposed in the Piers borane-catalysed hydroboration and 1,1-carboboration of alkynes with B(C6F5)3. (Figure presented.).
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.
Transborylation of alkenylboranes with diboranes
Bru, Gerard,Carbó, Jorge J.,Dominguez-Molano, Paula,Fernández, Elena,Maza, Ricardo J.,Salvado, Oriol
supporting information, p. 13361 - 13364 (2021/12/17)
Exchange of boryl moieties between alkenylboranes and diboron reagents has been postulated as a stereospecific cross-metathesis pathway with concomitant formation of mixed diboron reagents. DFT calculations propose a mechanism for the stereocontrolled C(sp2)-B/B′-B′ cross-metathesis with both symmetric and non-symmetric diboron reagents. This journal is
