Rhodium(I)/cationic 2,2′-bipyridyl-catalyzed [2+2+2] cycloaddition of α,ω-diynes with alkynes in water under air

Wang, Yunhua; Huang, Shao-Hsien; Lin, Tze-Chiao; Tsai, Fu‐Yu

doi:10.1016/j.tet.2010.06.088

Cited by 26 publications

(8 citation statements)

References 89 publications

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“…Recently, Tsai and coworkers reported that the cycloaddition of internal diyne with 1-hexyne did not proceed at all, and a nearly quantitative amount of internal diyne was recovered from the aqueous solution catalyzed by [Rh(COD)Cl] 2 /water-soluble cationic 2,2'-bipyridyl ligand in water. [22] To our satisfaction, internal diyne N,N-di(but-2-ynyl)-4-methylbenzenesulfonamide 2 g was successfully applied to the synthesis of 4 ga in 52 % yield under the optimized reaction conditions (entry 7). In accordance with these observations, the coupling of diyne 2 f and 3 a provided pyridine 4 fa as a single regioisomer in 53 % yield in the presence of KOH (entry 6).…”

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confidence: 95%

“…In accordance with these observations, the coupling of diyne 2 f and 3 a provided pyridine 4 fa as a single regioisomer in 53 % yield in the presence of KOH (entry 6). [22] This outcome might be elucidated by a mechanism in which the metallacyclopentadiene is selectively formed by oxidative coupling of two coordinated alkynes and inserted by a nitrile from the side with smaller steric hindrance, [2] which leads to the observed regioselectivity. In addition to chloroacetonitrile 3 a and dichloroacetonitrile 3 c, water soluble 2-bromoacetonitrile 3 b can be employed in the present protocol.…”

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confidence: 99%

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Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Wang

et al. 2012

ChemSusChem

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The transition metal-catalyzed [2+2+2] cycloaddition of two alkyne molecules and a nitrile, particularly involving catalysis by Co, Ru, Rh, Ni, Ti, and Fe species, [1][2][3][4][5][6] has been widely investigated as a valuable tool for the synthesis of substituted pyridines. [7,8] However, highly diluted conditions and techniques of slow addition are generally required to suppress the competing side reactions, such as dimerization and trimerization of the diynes. [9a] Despite substantial advances, metal-catalyzed [2+2+2] cycloaddition remains a formidable challenge. Thus, new tactics should be applied to the reaction, aimed at attenuating or controlling the side reactions. It has been shown that the Diels-Alder reaction can be intensified in aqueous media, [9b] and we expect that water can also expedite the [2+2+2] cycloaddition.Although the [2+2+2] cycloaddition reaction has been widely explored in the last few decades, there are only limited examples of the use of water as solvent (Scheme 1). Heller and co-workers reported that acetylene and nitriles in water efficiently undergo co-cyclization under visible-light irradiation in the presence of CpCo(COD) (COD: 1,5-cyclooctadiene) and its derivatives, resulting in excellent product selectivities and moderate yields. [10] Parsons and Jerome reported a reaction of hexyne and acetonitrile in supercritical water at 374 8C, affording the corresponding pyridine isomers in a yield of 15 %. [11] Eaton and co-workers showed that a water-soluble cobalt complex catalyzes the [2+2+2] cycloaddition of two alkyne molecules and a nitrile in a mixture of water and methanol at 85 8C, with a yield of up to 99 %. However, hydrophilic functional groups on the alkynes were necessary. [12] In 2002, Butenschçn reported another cobalt complex with pendant phosphane substituents on the cyclopentadienyl ring. These substituents made the cobalt complex stable in water, thus allowing the preparation of pyridine derivatives at room temperature in a mixture of water and ethanol. [13] In aqueous medium, acceleration of the cycloaddition by water should outweigh the lowered efficiency and reaction rate due to the highly dilute reaction conditions. [9] In addition, water can induce rate enhancements, [14] chemoselectivity, [15] and stereoselectivity [16] in numerous synthetic transformations. However, to the best of our knowledge mixed solvents or photochemical activation were necessary in previous works, and the cycloaddition of diynes and a nitrile in neat water without irradiation has never been reported. The development of a new catalytic system to circumvent these restrictions is still highly desirable.Generally, two crucial problems are encountered in the [2+2+2] cycloaddition of alkynes and nitriles in water: 1) the poor solubility of the metal precursor and substrates in pure water, and 2) easy hydrolysis of the nitriles in water under the reaction conditions. [17] To overcome these issues, we surmised that a water-soluble ligand might connect the metal precursor and substrates in th...

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confidence: 95%

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confidence: 99%

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Wang

et al. 2012

ChemSusChem

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“…A wide range of substrates have been investigated, including diynes and alkynes with high degree of steric hindrance, 40 perfluoroalkylacetylenes, 41 glycoside units bearing bis-propargyl ethers, 42 1-alkynylphosphine sulphides, 43 propargyl glycine aminoacids, 44 as well as synthetic equivalents of alkynes like enol ethers/acetates 45 or (Z)-(2-bromovinyl)trifluoroborate, 46 and even solid-supported diynes. 47 In addition, several rhodium(I) complexes were found to be very efficient as catalysts, obtained by treatment of a rhodium(I) precursor with proper ligands: 4,5-bis (2oxazolinyl)xanthene (Xabox), 48 N-phosphino t-butylsulfinamides (PNSO), 49 tris(meta-sulfonatophenyl)phosphine trisodium salt (tppts) 50 and a 2,2′-bipyridine cationic derivative 51 (both watersoluble), and more recently also N-heterocyclic carbenes supported on silica. 52 A very exciting application of Rh-catalyzed [2+2+2] cycloadditions is the enantioselective synthesis of axially chiral compounds bearing phthalan moieties, performed in the presence of enantiopure chiral ligands.…”

Section: [2+2+2] Cyclotrimerization Of Alkynesmentioning

confidence: 99%

“…Another simple procedure for the [2+2+2] cycloaddition of α,ωdiynes and alkynes in water was described by Tsai and coworkers. 51 The authors reported that [RhCl(cod)]2-2,2'-bipyridyl complex, bearing two quaternary ammonium moieties, can be used for the synthesis of N-tosyl isoindoline derivatives 157 in good yields (Scheme 59). Cheng and co-workers described 65 the first example of regio and chemoselective [2+2+2] cycloaddition reactions between 1,7heptadiynes 164 and allenes 165 in the presence of CoI2(PPh3)2/Zn system.…”

Section: Scheme 52 Synthesis Of Isoindolines Via Cycloaddition Reactionsmentioning

confidence: 99%

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines

Albano

Aronica

2018

Synthesis

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Oxygen and nitrogen heterocycles are present in a vast number of natural substrates and biologically active molecules. In particular, phthalan and isoindoline subunits are found in many classes of products such as antibiotics, antioxidants, antimycotics, pigments, and fluorophores. Therefore several procedures dedicated to the construction of these heterocycles have been developed. In this review, a detailed analysis of the literature data regarding the synthesis of these nuclei via cyclization reactions is reported.1 Introduction2 Phthalans2.1 Oxa-Pictet–Spengler Reaction2.2 Garratt–Braverman Cyclization2.3 Diels–Alder and Related Reactions2.4 [2+2+2] Cyclotrimerization of Alkynes2.5 Cycloetherification of ortho-Substituted Aromatics2.6 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions3 Isoindolines3.1 Amination of Dihalides3.2 Intramolecular Hydroamination3.3 Diels–Alder and Related Reactions3.4 [2+2+2] Cycloaddition Reactions3.5 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions4 Conclusions

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“…In the field of [2+2+2] cycloaddition reactions, few examples of the recyclability of catalytic systems have been reported. Among them, several strategies have been tested for the recovery of catalysts: i) the anchoring of a metal complex to a polystyrene resin;8 ii) the use of molten salts as immobilizing agents;9 iii) the use of a water soluble catalyst;10 iv) the immobilization of the ligand at the surface of a dendrimer,11 and v) the recovery of air stable complexes by column chromatography 12. In this field, the formation of hybrid silica materials is attractive as a means of achieving supported catalysts based on metal complexes.…”

Section: Introductionmentioning

confidence: 99%

Rhodium‐NHC Hybrid Silica Materials as Recyclable Catalysts for [2+2+2] Cycloaddition Reactions of Alkynes

et al. 2014

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Bis-silylated dihydroimidazolium salt 1 and monosilylated imidazolium salt 2 are transformed to (NHC)RhCl(COD) complexes 3 and 4, which allow the preparation of hybrid silica materials either by sol-gel or grafting processes. After a full characterization of the materials by means of solid state NMR, N2-sorption measurements, thermogravimetric analysis (TGA) and elemental analysis, the catalytic activity is evaluated in the [2+2+2] cycloaddition of alkynes. Excellent yields of the cycloadducts are obtained for up to six consecutive cycles with the grafted material, using a simple filtration to recover the catalyst. Both conventional and microwave heating prove to be effective for the process described.

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Rhodium(I)/cationic 2,2′-bipyridyl-catalyzed [2+2+2] cycloaddition of α,ω-diynes with alkynes in water under air

Cited by 26 publications

References 89 publications

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines

Rhodium‐NHC Hybrid Silica Materials as Recyclable Catalysts for [2+2+2] Cycloaddition Reactions of Alkynes

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Rhodium(I)/cationic 2,2′-bipyridyl-catalyzed [2+2+2] cycloaddition of α,ω-diynes with alkynes in water under air

Cited by 26 publications

References 89 publications

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines­

Rhodium‐NHC Hybrid Silica Materials as Recyclable Catalysts for [2+2+2] Cycloaddition Reactions of Alkynes

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Cyclization Reactions for the Synthesis of Phthalans and Isoindolines