Phosphorylated Polyacrylonitrile Fibers as an Efficient and Greener Acetalization Catalyst

Xu, Gang; Cao, Jian; Zhao, Yuchao; Zheng, Lishuo; Tao, Minli; Zhang, Wenqin

doi:10.1002/asia.201700846

Cited by 31 publications

(17 citation statements)

References 74 publications

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“…Indeed, these approaches have inherent limitations such as handling of corrosive acid catalyst, high temperature, longer reaction time, and limited substrates scope. In recent times, various catalytic methods including organocatalysts,– photo‐redox catalysts,– and heterogeneous catalysts– and transition‐metal catalysis have been reported in replacement of highly acidic conditions. Nevertheless, these methods require high catalyst loading and harsh reaction conditions.…”

Section: Methodsmentioning

confidence: 99%

Nickel‐Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions

Subaramanian

Landge

Mondal

et al. 2019

Chemistry An Asian Journal

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Am olecularly defined Ni II -complex catalyzing the chemoselective acetalization of aldehydes with alcohols under neutralc onditions is reported. The reactioni s general, efficient and showedawide substrate scope (including aliphatic aldehydes)a sw ell as excellent functional group tolerance. Reusability of the present nickel catalyst is also demonstrated.Development of new catalytic approaches, in particular,c atalysts based on cheap,e arth-abundant, non-precious metalsf or sustainable chemical synthesis is the key motivation in contemporary science. The carbonyl compounds such as aldehydes and ketones are the most significant functional groups in organic synthesis owing to their ubiquitous, andv ersatile reactivity.I nt he multi-stepo rganic transformations,ag reen protocol for the protection or maskingo fc arbonyl compounds that operate under neutralc onditions is highly required. In this regard, acetalization reaction using widespread alcohols hasa ttracted much interest. Acetals serve as an excellent protective group of carbonyl compounds [1] as well as they found various applicationsi nt he synthesis of chiral auxiliaries, steroids, flavoring agents, and pharmaceutical moieties. [2][3][4] In general, acetalization involves the condensation of carbonyl compounds with alcoholic substrates in the presence of Brçnsted/Lewis acid, mineral acid, or base catalysts. [5] However, these protocols often requireatoxic orthoformate as an alcohol source (for acetalization). Indeed,t hese approaches have inherentl imitations such as handling of corrosivea cid catalyst, high temperature, longer reaction time, and limited substrates scope. In recent times, variousc atalytic methods including or-ganocatalysts, [6a-f] photo-redox catalysts, [7a-c] and heterogeneous catalysts [8a-c] and transition-metal catalysis [9] have been reportedi nr eplacement of highly acidic conditions. Nevertheless, these methods require high catalystl oading and harsh reaction conditions.Recently,L yons et al. reported the acetalization of aldehydes in the presence of tropylium salt as organo-Lewisa cidc atalyst using triethyl orthoformate as alcohol source.T his methodr equiresh eating condition, longerr eactiont ime, and an excess amount of Na 2 SO 4 as the dehydrating agent for the cyclic acetalization. [10] Hudnall and co-workers reported antimony(V) catalyzed acetalization of aldehydesi nt he presence of as toichiometrica mount of either triethoxymethane or triethoxysilane, and the products can be purified by distillation processw hich limits the scope of this protocol for thermally stable substrates. [11] However, both of these methods require as toichiometric amount of toxic triethylo rthoformates and triethylo rthoformate/silicate, respectively.T hus, it would be of interest to develop as imple and eco-benign catalystt hat works under neutral and mild reaction conditions and avoid the use of toxic orthoformates. Here, we report am olecularly defined nickel(II) complex catalyzed acetalization of aldehydes using widespread alcohols. The re...

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Section: Methodsmentioning

confidence: 99%

Nickel‐Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions

Subaramanian

Landge

Mondal

et al. 2019

Chemistry An Asian Journal

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“…( E )‐2‐Styryl‐1,3‐dithiolane (5 d) : Following the general procedure, using cinnamaldehyde (0.132 g, 1.0 mmol), 1,2‐ethanedithiol (0.103 g, 1.1 mmol), eosin Y (0.6 mg, 0.1 mol%), then purified by column chromatography (SiO 2 , 10% ethyl acetate in hexanes) to provide 5 d as the yellow oil (0.073 g, 35% yield). 1 H NMR (400 MHz, CDCl 3 ): δ 7.38–7.36 (m, 2H), 7.32–7.28 (m, 2H), 7.26–7.21 (m, 1H), 6.51 (d, J =16.0 Hz, 1H), 6.21 (dd, J =16.0, 8.0 Hz, 1H), 5.23 (d, J =8.0 Hz, 1H), 3.41–3.25 (m, 4H).…”

Section: Methodsmentioning

confidence: 99%

Visible‐Light Photoredox‐Catalyzed Thioacetalization of Aldehydes Under Metal‐Free and Solvent‐Free Conditions

Wang

Basha

et al. 2018

Adv Synth Catal

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A first visible-light photoredox-catalyzed thioacetalization of aldehydes under metal-free and solvent-free conditions is described. Under blue LED irradiation, a reactive thiyl radical was initially generated through single-electron oxidation of thiol, which subsequently reacted with aldehydes to afford dithioacetals following a radical mechanism. The reaction proceeded under ambient conditions, and a wide range of acyclic and cyclic dithioacetal derivatives were afforded in good to excellent yields.

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“…Tao, Zhang and co-workers reported the use of amine-functionalized polyacrylonitrile fibers (PANF) for the immobilization of phosphoric acid scaffolds which was next involved in batch and flow acetalization of aldehydes. [157] The polyacrylonitrile fiber was first reacted with ethanolamine, next with POCl 3 and then a final hydrolysis gave the functionalized PANF 268 (Figure 71).…”

Section: Supported Phosphoric Acidsmentioning

confidence: 99%

“…Continuous flow acetalization of benzaldehyde using phosphoric acid-functionalized polyacrylonitrile fibers. [157] ization through a packed-bed column filled with 268 proceeded under mild conditions (room temp. in flow vs. 65°C in batch).…”

Section: Supported Phosphoric Acidsmentioning

confidence: 99%

Continuous Flow Organophosphorus Chemistry

2020

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Organophosphorus derivatives are widespread compounds that chemists find from the bench to the plant, with numerous daily life applications. Besides their common utility for a wide range of notorious reactions such as the Wittig and Horner‐Wadsworth‐Emmons olefinations, the Arbuzov reaction, the Staudinger reaction, the Mitsunobu reaction as well as ligands for a large variety of organometallic complexes, organophosphorus compounds have also found numerous applications as active pharmaceutical ingredients and agrochemicals. Some organophosphorus derivatives are also infamously known as Chemical Warfare Agents. Within the context of generalized adoption of new process technologies in the Chemistry Toolbox, this review intends to give an update on the most recent and significant advances in continuous flow organophosphorus chemistry. Selected examples in methodology, total synthesis and for the preparation of industrially relevant targets are discussed for illustrating the assets of flow chemistry.

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Phosphorylated Polyacrylonitrile Fibers as an Efficient and Greener Acetalization Catalyst

Cited by 31 publications

References 74 publications

Nickel‐Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions

Nickel‐Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions

Visible‐Light Photoredox‐Catalyzed Thioacetalization of Aldehydes Under Metal‐Free and Solvent‐Free Conditions

Continuous Flow Organophosphorus Chemistry

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