2928-43-0Relevant academic research and scientific papers
Redox-active ligand based Mn(i)-catalyst for hydrosilylative ester reduction
Chakraborty, Soumi,Das, Arpan,Mandal, Swadhin K.
supporting information, p. 12671 - 12674 (2021/12/04)
Herein a Mn(i) catalyst bearing a redox-active phenalenyl (PLY) based ligand is reported for the efficient hydrosilylation of esters to alcohols using the inexpensive silane source polymethylhydrosiloxane (PMHS) under mild conditions. Mechanistic investigations suggest a strong ligand-metal cooperation where a ligand-based single electron transfer (SET) process initiates the reaction through Si-H bond activation.
Visible Light Induced Reduction and Pinacol Coupling of Aldehydes and Ketones Catalyzed by Core/Shell Quantum Dots
Xi, Zi-Wei,Yang, Lei,Wang, Dan-Yan,Feng, Chuan-Wei,Qin, Yufeng,Shen, Yong-Miao,Pu, Chaodan,Peng, Xiaogang
, p. 2474 - 2488 (2021/02/05)
We present an efficient and versatile visible light-driven methodology to transform aryl aldehydes and ketones chemoselectively either to alcohols or to pinacol products with CdSe/CdS core/shell quantum dots as photocatalysts. Thiophenols were used as proton and hydrogen atom donors and as hole traps for the excited quantum dots (QDs) in these reactions. The two products can be switched from one to the other simply by changing the amount of thiophenol in the reaction system. The core/shell QD catalysts are highly efficient with a turn over number (TON) larger than 4 × 104 and 4 × 105 for the reduction to alcohol and pinacol formation, respectively, and are very stable so that they can be recycled for at least 10 times in the reactions without significant loss of catalytic activity. The additional advantages of this method include good functional group tolerance, mild reaction conditions, the allowance of selectively reducing aldehydes in the presence of ketones, and easiness for large scale reactions. Reaction mechanisms were studied by quenching experiments and a radical capture experiment, and the reasons for the switchover of the reaction pathways upon the change of reaction conditions are provided.
Efficient and chemoselective hydrogenation of aldehydes catalyzed by well-defined PN3-pincer manganese(ii) catalyst precursors: An application in furfural conversion
Gholap, Sandeep Suryabhan,Dakhil, Abdullah Al,Chakraborty, Priyanka,Li, Huaifeng,Dutta, Indranil,Das, Pradip K.,Huang, Kuo-Wei
supporting information, p. 11815 - 11818 (2021/11/30)
Well-defined and air-stable PN3-pincer manganese(ii) complexes were synthesized and used for the hydrogenation of aldehydes into alcohols under mild conditions using MeOH as a solvent. This protocol is applicable for a wide range of aldehydes containing various functional groups. Importantly, α,β-unsaturated aldehydes, including ynals, are hydrogenated with the CC double bond/CC triple bond intact. Our methodology was demonstrated for the conversion of biomass derived feedstocks such as furfural and 5-formylfurfural to furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol respectively.
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
, p. 2842 - 2850 (2021/02/01)
Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
Pyridine-based hypercrosslinked polymers as support materials for palladium photocatalysts and their application in Suzuki-Miyaura coupling reactions
Zhang, Yan,Zhang, Le,Zhang, Xiaoli,Yang, Didi,Du, Cheng,Wan, Liu,Au, Chaktong,Chen, Jian,Xie, Mingjiang
, p. 15202 - 15208 (2020/09/23)
A series of hypercrosslinked polymers (P1 to P8) was synthesized from pyridine and conjugated monomers to support palladium for photocatalytic Suzuki-Miyaura coupling reactions. The results of SEM, TEM and XRD analyses reveal that the supports possess a loose porous amorphous lamellar structure, and the TGA test shows that they are thermally stable. Among the prepared photocatalysts, the one using P6 as a support performed the best, displaying excellent photocatalytic and recycling performance under the irradiation of blue light at 30 °C.
Pd-catalyzed atom-efficient cross-coupling of triarylbismuth reagents with protecting group-free iodophenylmethanols: Synthesis of biarylmethanols
Meka, Suresh,Rao, Maddali L. N.
supporting information, (2020/02/11)
An atom-efficient procedure for the synthesis of functionalized biarylmethanols via the Pd-catalyzed cross-coupling reactions of differently functionalized iodophenylmethanols and triarylbismuth reagents is described. This protecting group-free direct couplings of 2-, 3- or 4-iodophenylmethanols with triarylbismuth reagents afforded biarylmethanols in good to high yields.
Ir(I)-Catalyzed Synthesis of (E)-4-Benzylidenylacridines and (E)-2-Styrylquinoline-3-carboxamide through Sequential Suzuki–Miyaura Coupling, Dehydrogenative Friedl?nder Reaction, and sp3-C–H Activation
Prameela, Soda,Nawaz Khan, Fazlur-Rahman
, p. 5394 - 5410 (2020/08/27)
An efficient one-pot strategy evolved in the synthesis of (E)-4-benzylidenylacridin-1(2H)-ones, (4 or 9) (E)-2-styryl quinoline-3-carboxamides (5 or 10) by sequential Suzuki–Miyaura coupling-dehydrogenative Friedl?nder-sp3 C–H activation. The 2-amino-5-chloro benzhydrol 1, aromatic alcohol 2 or 6 ketones 3 or 3', and phenylboronic acid 7 underwent a smooth reaction in a basic deep eutectic solvent consisting of K2CO3 and ethylene glycol (DES-1,1:1). DES-1 could enable the Pd-catalyzed Suzuki coupling reaction of 6, as well as the rapid oxidation of primary, secondary, and Suzuki coupled primary alcohols (2, 1, and 8) in the presence of an iridium catalyst and 1,10-phenanthroline. The acidic DES-2 (dimethyl urea/tartaric acid, 7:3) assists the Friedl?nder annulation and subsequent sp3-C–H functionalization resulting in (E)-4-benzylidenylacridin-1(2H)-ones (4 or 9) and (E)-2-styryl quinoline-3-carboxamides (5 or 10).
6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine
Kobayashi, Eiji,Kishi, Atsushi,Togo, Hideo
, p. 7335 - 7347 (2019/11/22)
Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of Sc(OTf)3 in toluene, followed by the reaction with molecular iodine and K2CO3 in a mixture of THF and methanol at 60 °C gave the corresponding 6-arylphenanthridines in good to moderate yields. The present reaction is a one-pot method for the preparation of 6-arylphenanthridines from aryl o-biaryl ketones through the cyclization of imino-nitrogen-centered radicals that were generated from N-iodo aryl o-biaryl ketimines formed from the reaction of aryl biaryl ketimines with molecular iodine.
Borinic Acid Mediated Hydrosilylations: Reductions of Carbonyl Derivatives
Chardon, Aurélien,Rouden, Jacques,Blanchet, Jér?me
supporting information, p. 995 - 998 (2018/12/13)
4-Fluoro-2-chlorophenylborinic acid acts as a precatalyst in the presence of phenylsilane for the facile reduction of ketones, aldehydes and imines. Notably, synergistic mediation of a tertiary amine was found essential to trigger silicon to boron hydride transfer to generate a key amine–diarylhydroborane Lewis complex.
