Sodium tungstate-catalyzed “On-water” synthesis of β-arylvinyl bromides

Roy, Swapnila; Bhar, Sanjay

doi:10.1080/17518253.2010.491095

Cited by 11 publications

(10 citation statements)

References 46 publications

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“…A series of works was devoted to the generation of Br + from an alkali halide using transition metal peroxo-complexes. − Thus, a “green variant of the Hunsdiecker reaction” was suggested involving a Na 2 MoO 4 /H 2 O 2 agent for generation of the bromonium ion from KBr (Scheme ). Unfortunately, satisfactory yields of β-bromostyrenes were reached only for nonsubstituted 4-methoxy and 4-chlorocinnamic acids (65 and 85%, respectively).…”

Section: Halodecarboxylation Of αβ-Unsaturated Carboxylic Acidssupporting

confidence: 79%

Decarboxylative Halogenation of Organic Compounds

2020

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Decarboxylative halogenation, or halodecarboxylation, represents one of the fundamental key methods for the synthesis of ubiquitous organic halides. The method is based on conversion of carboxylic acids to the corresponding organic halides via selective cleavage of a carbon–carbon bond between the skeleton of the molecule and the carboxylic group and the liberation of carbon dioxide. In this review, we discuss and analyze major approaches for the conversion of alkanoic, alkenoic, acetylenic, and (hetero)aromatic acids to the corresponding alkyl, alkenyl, alkynyl, and (hetero)aryl halides. These methods include the preparation of families of valuable organic iodides, bromides, chlorides, and fluorides. The historic and modern methods for halodecarboxylation reactions are broadly discussed, including analysis of their advantages and drawbacks. We critically address the features, reaction selectivity, substrate scopes, and limitations of the approaches. In the available cases, mechanistic details of the reactions are presented, and the generality and uniqueness of the different mechanistic pathways are highlighted. The challenges, opportunities, and future directions in the field of decarboxylative halogenation are provided.

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Section: Halodecarboxylation Of αβ-Unsaturated Carboxylic Acidssupporting

confidence: 79%

Decarboxylative Halogenation of Organic Compounds

2020

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“…Given that W-h 2 -peroxy intermediate has more charged metal ion-bearing larger-radii (W 6+ , 60 pm versus V 5+ 46 pm) and longer O-O bonds than those of V-h 2 -peroxy intermediate (151, 153 pm for W, 143-146 nm for V) (Reynlds and Butler, 1996;Amato et al, 1986;Mimoun et al, 1983;Drew and Einstein, 1972;Stomberg, 1986;Djordjevic et al, 1985;Begin et al, 1975), it is supposed to be a better peroxy electrophile as observed in oxidation of (thiolato)-cobalt (III) complexes (Ghiron and Thompson, 1988). Meanwhile, the electrophilicity of W-h 2 -peroxy, we believe, can be further enhanced by Brønsted or Lewis acid (Kikushima et al, 2010), promoting the formation of hypohalous species (W-III, HOX) (Roy and Bhar, 2010). From this perspective, biomimetic W-catalyzed halogenation under mild pH could be possible (Figure 1C, II).…”

Section: Introductionmentioning

confidence: 90%

“…Initially, the tungstate W-V would form W-h 2peroxy intermediate W-V and then W-I in the presence of H 2 O 2 and HOAc. The peroxy moiety in W-I was opened by halide (Roy and Bhar, 2010) HOAc (1.0 equiv. )…”

Section: Proposed Reaction Mechanismmentioning

confidence: 99%

Tungstate-Catalyzed Biomimetic Oxidative Halogenation of (Hetero)Arene under Mild Condition

Liao

et al. 2020

iScience

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Aryl halide (Br, Cl, I) is among the most important compounds in pharmaceutical industry, material science, and agrochemistry, broadly utilized in diverse transformations. Tremendous approaches have been established to prepare this scaffold; however, many of them suffer from atom economy, harsh condition, inability to be scaled up, or cost-unfriendly reagents and catalysts. Inspired by vanadium haloperoxidases herein we presented a biomimetic approach for halogenation (Br, Cl, I) of (hetero)arene catalyzed by tungstate under mild pH in a costefficient and environment-and operation-friendly manner. Broad substrates, diverse functional group tolerance, and good chemo-and regioselectivities were observed, even in late-stage halogenation of complex molecules. Moreover, this approach can be scaled up to over 100 g without time-consuming and costly column purification. Several drugs and key precursors for drugs bearing aryl halides (Br, Cl, I) have been conveniently prepared based on our approach.

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“…Aromatic bromides are an important class of compounds, which are commonly utilized as the coupling partner in transition-metal-catalyzed cross-coupling reactions [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. Thus, the development of a synthetic method of arylbromides has attracted tremendous efforts [ 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ]. Among them, much progress has been made on palladium-catalyzed regioselective bromination of C–H bonds using different agents.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Umpolung of Bromide: Transition-Metal-Free Bromination of Indole C–H Bond

et al. 2019

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A facile and sustainable electrochemical umpolung of bromide ion protocol was developed under mild reaction conditions. Transition metal catalysts and exogenous chemical oxidants were obviated for the bromination of C–H bond. Notably, graphite rod, which is commercially available at supermarkets and is inexpensive, was employed as the electrode material. This operationally easy and environmentally friendly approach accomplished the synthesis of 3-bromoindole in excellent yield and regioselectivity.

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Sodium tungstate-catalyzed “On-water” synthesis of β-arylvinyl bromides

Cited by 11 publications

References 46 publications

Decarboxylative Halogenation of Organic Compounds

Decarboxylative Halogenation of Organic Compounds

Tungstate-Catalyzed Biomimetic Oxidative Halogenation of (Hetero)Arene under Mild Condition

Electrochemical Umpolung of Bromide: Transition-Metal-Free Bromination of Indole C–H Bond

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