Lanthanide Silylamide-Catalyzed Synthesis of Pyrano[2,3-<i>b</i>]indol-2-ones

Chen, Qifa; Teng, Yue; Xu, Fan

doi:10.1021/acs.orglett.1c01506

Cited by 20 publications

(5 citation statements)

References 38 publications

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“…Obviously, it is greatly different from the C–C coupling reaction between Ti or Zr metallacyclopropenes and two nitriles with the isolation of the structurally characterized diazametallacyclopentadienes. , Though the result is similar to that of lithium β-diketiminates resulting from LiCHR 2 with 2 equiv of nitriles, other metals except for Li metal have seldom been reported to date . In general, β,β′-bis(aryl)substituted diketiminates are difficult to synthesize by virtue of the classical condensation reaction of a β-diketone with a suitable amine due to the steric hindrance as well as by aryl-substituted ketoimine complexation reactions, which could be realized by the reaction of a metal alkyl with 2 equiv of a nitrile or the reaction of a metal 1-azaallyl with 1 equiv of a nitrile. ,, …”

Section: Resultsmentioning

confidence: 99%

Reactivity of Rare Earth Metal Alkyl Complexes with Nitriles or Isonitrile: Versatile Ways toward Multiply Functionalized β-Diketiminato, (Iso)indolyl, and Imidazolyl Chelating Rare Earth Metal Complexes

Guo,

Hong,

Huang

et al. 2024

Inorg. Chem.

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The reactivity of the rare earth metal alkyl complexes LRE(CH 2 SiMe 3 )(THF) 2 (1 RE ) [RE = Y (1 Y ), Yb (1 Yb ), Lu (1 Lu ); L = 2,5-[(2-pyrrolyl)CPh 2 ] 2 (N-methylpyrrole)] with various nitriles and isonitriles has been fully developed. Treatment of the yttrium monoalkyl complex (1 Y ) with 2 equiv of aromatic nitriles afforded the symmetric trisubstituted βdiketiminato yttrium complexes (2 Y(H) , 2 Y(Me) , and 2 Y(F) ) through successive cyano group insertion into the RE−C bond and 1,3-H shift or the unsymmetric trisubstituted β-diketiminato yttrium complex (3 Y ) unexpectedly via a 1,3-SiMe 3 shift when 4-(trifluoromethyl)benzonitrile was used in this reaction under the same conditions. By treating 1 Y with 2 equiv of tolyl acetonitrile, an activation of the sp 3 C−H bond occurred to form the corresponding β-aryl keteniminato complexes 4 Y(p-tol) and 4 Y(m-tol) . Remarkably, a heteroleptic cleavage of the CO−CN bond took place in the reaction of 1 Y with benzoyl nitrile, affording the unsymmetric trinuclear yttrium complex 5 Y bridged by three cyanide groups. Dinuclear ytterbium and lutetium complexes 6 Yb and 6 Lu containing a functionalized isoindole fragment were synthesized from the reactions of 1 with phthalonitrile by tandem insertion and cyclization. Further studies indicated that the temperature and stoichiometric ratio have a great influence on the reactivity patterns between the reactions of 1 RE with benzylisonitrile: two tetrasubstituted β-diketiminato complexes 8 and 9 were obtained at −30 °C, and tetrasubstituted imidazolyl yttrium and lutetium complexes 7 were isolated at elevated temperature, respectively. In addition, the tetrasubstituted β-diketiminato complexes 8 and 9 could be irreversibly converted to the cyclization products 7 by elevating the reaction temperature not only on the NMR scale but also on the preparative scale. Notably, when the phenyl isonitrile instead of benzyl isonitrile was reacted with 1 Yb , a 2,3functionalized indolyl ytterbium complex 10 Yb was isolated.

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Section: Resultsmentioning

confidence: 99%

Reactivity of Rare Earth Metal Alkyl Complexes with Nitriles or Isonitrile: Versatile Ways toward Multiply Functionalized β-Diketiminato, (Iso)indolyl, and Imidazolyl Chelating Rare Earth Metal Complexes

Guo,

Hong,

Huang

et al. 2024

Inorg. Chem.

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“…An exploratory experiment focusing on the chiral induction of spirooxindoline yielded moderate enantioselectivity. A comparable methodology has been used for the synthesis of pyrano [2,3-b]indol-2-ones, with the oxindoline phosphates being generated in situ [ 172 ].…”

Section: Transition-metal-free Substitution Reactions Of Organophosph...mentioning

confidence: 99%

Organophosphates as Versatile Substrates in Organic Synthesis

Oeser,

Tobrman

2024

Molecules

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This review summarizes the applications of organophosphates in organic synthesis. After a brief introduction, it discusses cross-coupling reactions, including both transition-metal-catalyzed and transition-metal-free substitution reactions. Subsequently, oxidation and reduction reactions are described. In addition, this review highlights the applications of organophosphates in the synthesis of natural compounds, demonstrating their versatility and importance in modern synthetic chemistry.

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“…In 2021, Chen et al successfully synthesized a series of tetrasubstituted pyrano[2,3- b ]indol-2(9 H )-ones 109a–l in 65–91% yield via the reaction between substituted isatines 40 and diaryl cyclopropenones 1 at 110 °C in toluene and in the presence of lanthanide amides [(Me 3 Si) 2 N] 3 La(μ-Cl)Li(THF) 3 and ligand 108 as a catalyst (Scheme 67). 109…”

Section: Chemistrymentioning

confidence: 99%