38115-81-0Relevant academic research and scientific papers
Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
supporting information, p. 1045 - 1055 (2022/01/19)
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
Direct anodic (thio)acetalization of aldehydes with alcohols (thiols) under neutral conditions, and computational insight into the electrochemical formation of the acetals
Liu, Caiyan,Shen, Yongli,Xiao, Zihui,Yang, Hui,Han, Xue,Yuan, Kedong,Ding, Yi
, p. 4030 - 4034 (2019/08/07)
A versatile protocol for the production of acetals/thioacetals by means of direct electrochemical oxidation is developed here under neutral conditions, providing (thio)acetals with good functional group tolerance and a wide scope for both aldehydes and (thio)alcohols. DFT calculations reveal that direct electron transfer from the anode plays a key role in carbonyl activation during this acid free acetalization process.
Ru(II)-functionalized SBA-15 as highly chemoselective, acid free and sustainable heterogeneous catalyst for acetalization of aldehydes and ketones
Lazar, Anish,Betsy,Vinod,Singh
, p. 62 - 66 (2017/10/31)
Combining electron deficient Ru(II) coordination sites with organofunctionalized SBA-15, (L)Ru(II)@SBA-15, result in a mild, neutral, water scavenger free and chemo-selective acetalization catalyst for cyclic/acyclic acetals. Vacant coordination sites of ruthenium in (L)Ru(II)@SBA-15 activates protecting groups as well as reactants simultaneously and restricts the reverse acetalization reaction. Synthesized (L)Ru(II)@SBA-15 catalyst has been thoroughly characterized and act as competitive catalyst compared to conventional acid catalysts. (L)Ru(II)@SBA-15 performs high catalytic activity as well as selectivity within 20 min with high TOF. The catalyst can be recycled and reaction parameters are optimized.
Preparation of acetals from aldehydes and alcohols under basic conditions
Grabowski, Jakub,Granda, Jaros?aw M.,Jurczak, Janusz
, p. 3114 - 3120 (2018/05/17)
A new, simple protocol for the synthesis of acetals under basic conditions from non-enolizable aldehydes and alcohols has been reported. Such reactivity is facilitated by a sodium alkoxide along with a corresponding trifluoroacetate ester, utilizing formation of sodium trifluoroacetate as a driving force for acetal formation. The usefulness of this protocol is demonstrated by its orthogonality with various acid-sensitive protecting groups and by good compatibility with functional groups, delivering synthetically useful acetals complementarily to the synthesis under acidic conditions from aldehydes and alcohols.
A Ta/W mixed addenda heteropolyacid with excellent acid catalytic activity and proton-conducting property
Li, Shujun,Peng, Qingpo,Chen, Xuenian,Wang, Ruoya,Zhai, Jianxin,Hu, Weihua,Ma, Fengji,Zhang, Jie,Liu, Shuxia
, p. 1 - 7 (2016/08/12)
A new HPAs H20[P8W60Ta12(H2O)4(OH)8O236]·125H2O (H-1) which comprises a Ta/W mixed addenda heteropolyanion, 20 protons, and 125 crystalline water molecules has been prepared through ion-exchange method. The structure and properties of H-1 have been explored in detail. AC impedance measurements indicate that H-1 is a good solid state proton conducting material at room temperature with a conductivity value of 7.2×10?3?S?cm?1 (25?°C, 30% RH). Cyclic voltammograms of H-1 indicate the electrocatalytic activity towards the reduction of nitrite. Hammett acidity constant H0 of H-1 in CH3CN is ?2.91, which is the strongest among the present known HPAs. Relatively, H-1 exhibits excellent catalytic activities toward acetal reaction.
Method for synthesizing bis-ether compound by catalyzing benzaldehyde through mixed type heteropoly acid
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Paragraph 0015; 0016, (2017/05/18)
The invention discloses a method for synthesizing a bis-ether compound by catalyzing benzaldehyde through mixed type heteropoly acid. Benzaldehyde and an alcohol compound are used as raw materials and mixed type heteropoly acid is used as a catalyst, so as to conduct reaction to prepare the bis-ether compound, wherein the alcohol compound is methanol, n-butanol or ethylene glycol, the molecular formula of mixed type heteropoly acid is H20[P8W60Ta12(H2O)4(OH)8O236].125H2O, and mixed type heteropoly acid is formed by one tetrameric Ta/W mixed type heteropoly anion, 20 protons and 125 crystal water molecules. Prepared mixed type heteropoly acid has the strongest acidity in heteropoly acid known at present, and has higher acid catalytic activity due to the strong acidity.
Catalytic synthesis of γ-alkoxy-α-keto esters
Krebs, Anke,Bolm, Carsten
supporting information; experimental part, p. 671 - 673 (2011/05/16)
Copper(II) triflate effectively catalyzes the reaction of (trimethylsilyloxy)acrylic esters and acetals to form -alkoxy - keto esters. The reaction proceeds under mild conditions providing products in good to excellent yields. The substrate scope was investigated, and it was demonstrated that the products could be converted into related compounds such as γ-hydroxy -α- keto esters and α-oximes. Georg Thieme Verlag Stuttgart - New York.
An unusual reaction of α-alkoxyphosphonium salts with Grignard reagents under an O2 atmosphere
Fujioka, Hiromichi,Goto, Akihiro,Otake, Kazuki,Kubo, Ozora,Sawama, Yoshinari,Maegawa, Tomohiro
supporting information; experimental part, p. 9894 - 9896 (2011/10/09)
An unusual and novel reaction of α-alkoxyphosphonium salts, generated from O,O-acetals and Ph3P, with Grignard reagents under an O 2 atmosphere afforded alcohols in moderate to high yields. It was clarified by isotopic labelling experiments that the reaction proceeded via a novel radical pathway.
Reductive coupling of aromatic dialkyl acetals using the combination of zinc and chlorotrimethylsilane in the presence of potassium carbonate
Hatano, Bunpei,Nagahashi, Keita,Habaue, Shigeki
, p. 1418 - 1419 (2008/03/14)
The treatment of aromatic acetals with zinc and chlorosilane in the presence of potassium carbonate in toluene brought about facile and effective reductive coupling to give the corresponding coupling products. Copyright
Lewis acid-promoted intermolecular acetal-initiated cationic polyene cyclizations
Zhao, Yu-Jun,Chng, Shu-Sin,Loh, Teck-Peng
, p. 492 - 493 (2007/10/03)
This paper describes a highly efficient intermolecular biomimetic polyene cyclization method using acetal as initiators. Both good yield and asymmetric induction were obtained. Copyright
