Direct Construction of Bicyclic Heterocycles by Palladium-Catalyzed Domino Cyclization of Propargyl Bromides

Ohno, Hiroaki; Okano, Akinori; Kosaka, Shohei; Tsukamoto, Koji; Ohata, Miyo; Ishihara, Kotaro; Maeda, Hatsuo; Tanaka, Tetsuaki; Fujii, Nobutaka

doi:10.1021/ol800063d

Cited by 44 publications

(6 citation statements)

References 24 publications

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“…Ohno has imaginatively constructed bicyclic heterocycles by palladium catalyzed domino cyclization of propargyl bromides 15. Yoshida has devised a clever palladium catalyzed three component coupling of propargylic oxiranes, phenols, and carbon dioxide 16.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes

et al. 2008

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PMe3 adds selectively to the central carbon of the η3– propargyl complex [C5Me5(CO)2Re(η3-CH2C≡CCMe3)][BF4] (1-t-Bu) to form the metallacyclobutene [C5Me5(CO)2Re(CH2C(PMe3)=CCMe3)][BF4] (7). The rate of rearrangement of the metallacyclobutene 7 to η2-alkyne complex [C5Me5(CO)2Re(η2-Me3PCH2C≡CCMe3)][BF4] (8) is is independent of phosphine concentration, consistent with a dissociative mechanism proceeding via η3-propargyl complex 1-t-Bu. The rate of this rearrangement is 480 times slower than the rate of exchange of PMe3 with the labeled metallacyclobutene 7-d9. This rate ratio provides an indirect measurement of the regioselectivity for addition of PMe3 to the central carbon of η3–propargyl complex 1-t-Bu to give 7 compared to addition to a terminal carbon to give 8. The addition of PPh3 to 1-t-Bu gives the metallacyclobutene [C5Me5(CO)2Re(CH2C(PPh3)=CCMe3)][BF4] (11). Low temperature 1H NMR spectra provide evidence for an equilibrium between metallacyclobutene 11 and η3-propargyl complex 1-t-Bu (Keq ≈ 44 M−1 at −46 °C and ΔG° (0 °C) = −1.2 ± 0.2 kcal mol−1).

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Section: Introductionmentioning

confidence: 99%

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes

et al. 2008

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“…[6] More recently, Ohno et al reported the first Pd-catalyzed intramolecular Heck-type reaction of oxime ethers with an aryl halide moiety to give indolin-3one O-alkyl oximes. [7,8] Good stereoselectivity (up to > 98:2 Z selectivity) was observed for the reaction irrespective of the isomeric ratio of the starting material. In 2008, Cheng et al reported the annulations between aromatic aldoxime ethers and aryl iodides through Pd-catalyzed C À H activation and subsequent intramolecular oxidative Heck cyclization.…”

Section: Introductionmentioning

confidence: 92%

Heck‐Type Reactions of Imine Derivatives: A DFT Study

Zhang

et al. 2010

Chemistry An Asian Journal

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The mechanism of a recently discovered intramolecular Heck-type coupling of oximes with aryl halides (Angew. Chem. Int. Ed. 2007, 46, 6325) was systematically studied by using density functional methods enhanced with a polarized continuum solvation model. The overall catalytic cycle of the reaction was found to consist of four steps: oxidative addition, migratory insertion, beta-H elimination, and catalyst regeneration, whereas an alternative base-promoted C-H activation pathway was determined to be less favorable. Migratory insertion was found to be the rate determining step in the catalytic cycle. The apparent activation barrier of migratory insertion of the (E)-oxime was +20.5 kcal mol(-1), whereas the barrier of (Z)-oxime was as high as +32.7 kcal mol(-1). However, (Z)-oxime could isomerize to form the more active (E)-oxime with the assistance of K(2)CO(3), so that both the (E)- and (Z)-oxime substrates could be transformed to the desired product. Our calculations also indicated that the Z product was predominant in the equilibrium of the isomerization of the imine double bond, which constituted the reason for the good Z-selectivity observed for the reaction. Furthermore, we examined the difference between the intermolecular Heck-type reactions of imines and of olefins. It was found that in the intermolecular Heck-type coupling of imines, the apparent activation barrier of migratory insertion was as high as +35 kcal mol(-1), which should be the main obstacle of the reaction. The analysis also revealed the main problem for the intermolecular Heck-type reactions of imines, which was that the breaking of a C=N pi bond was much more difficult than the breaking of a C=C pi bond. After systematic examination of a series of substituted imines, (Z)-N-amino imine and N-acetyl imine were found to have relatively low barriers of migratory insertion, so that they might be possible substrates for intermolecular Heck-type coupling.

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“…100 Ohno et al reported that the palladium-catalyzed domino cyclizations of propargyl bromides 130, possessing two nucleophilic functional groups, with catalytic tetrakis(triphenylphosphine)palladium(0) in the presence of sodium hydride in methanol gave 2,7-diazabicyclo[4.3.0]non-5-enes 132 in good yields (Scheme 43). 101 The regioselectivity of the reaction was entirely controlled by the relative reactivity of the amine functional groups, irrespective of the position of the nucleophiles. Lautens and co-workers reported 102 a one-pot procedure combining the copper-catalyzed Huisgen cycloadditions of alkynes and azides (CuAAC) 103 and palladium-catalyzed direct annulation by C-H bond activation 104 for the synthesis of structurally unique polycyclic frameworks 134 in good to excellent yields (62-97%) from different heterocycle-substituted aryliodoacetylenes 133.…”

Section: Scheme 40mentioning

confidence: 99%

Recent Developments in Palladium-Catalyzed Formation of Five- and Six-Membered Fused Heterocycles

Majumdar¹,

Samanta²,

Sinha³

2012

Synthesis

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Palladium-mediated cyclization reactions have been recognized as some of the simplest and useful tools for regio-as well as stereoselective syntheses of carbo-and heterocyclic compounds. In the multi-step syntheses of natural products it is frequently used as one of the most important steps. In this review article, we have summarized the various ways of constructing five-and six-membered heterocyclic rings by palladium-catalyzed intramolecular cyclizations published between 2008 and 2010.

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Direct Construction of Bicyclic Heterocycles by Palladium-Catalyzed Domino Cyclization of Propargyl Bromides

Cited by 44 publications

References 24 publications

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes

Heck‐Type Reactions of Imine Derivatives: A DFT Study

Recent Developments in Palladium-Catalyzed Formation of Five- and Six-Membered Fused Heterocycles

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Direct Construction of Bicyclic Heterocycles by Palladium-Catalyzed Domino Cyclization of Propargyl Bromides

Cited by 44 publications

References 24 publications

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η3-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η3-Propargyl Rhenium Complexes and Rhenacyclobutenes

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η3-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η3-Propargyl Rhenium Complexes and Rhenacyclobutenes

Heck‐Type Reactions of Imine Derivatives: A DFT Study

Recent Developments in Palladium-Catalyzed Formation of Five- and Six-Membered Fused Heterocycles

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Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes

Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η³-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η³-Propargyl Rhenium Complexes and Rhenacyclobutenes