Cyclo-oligomerization and rearrangement of some phenylated diynes by the RhCl3Aliquat 336 and by the H2PtCl6Aliquat 336 catalysts under phase transfer conditions

Badrieh, Yacoub; Blum, Jochanan; Amer, Ibrahim; Peter, K.; Vollhardt, C.

doi:10.1016/0304-5102(91)80022-u

Cited by 35 publications

(8 citation statements)

References 16 publications

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“…Earlier efforts by Müller and co‐workers, with these substrates using stoichiometric amounts of PdCl 2 , PtCl 2 , PtCl 4 , AuCl 3 , AuCl, or Na[AuCl 4 ] all showed low selectivity (even worse, for gold “catalysts”, a yield of only 1 % was achieved, which corresponds to 0.02 turnovers, that is, a 50‐fold excess of gold with regard to the product formed); the authors proposed a radical mechanism and thus subsequently also investigated photochemical conversions without metal catalyst, which delivered a different product in 3 % yield . In 1991, Blum and Vollhardt succeeded in improving Müller's conditions, achieving a yield of 80 % under quite forcing conditions (120 °C) in a biphasic water/dichloromethane mixture with a phase‐transfer catalyst and H 2 [PdCl 4 ] (5 mol %) after 16 h; again, no mechanistic insight was obtained . With respect to the substrate, a similar publication by Liu and co‐workers should be mentioned; while the authors assumed that a different mechanism is operating, they speculated about a possible mechanism involving vinyl cations only in a footnote.…”

Section: Methodsmentioning

confidence: 99%

On the Gold‐Catalyzed Generation of Vinyl Cations from 1,5‐Diynes

et al. 2017

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Conjugated 1,5-diynes bearing two aromatic units at the alkyne termini were converted in the presence of a gold catalyst. Under mild conditions, aryl-substituted dibenzopentalenes were generated. Calculations predict that aurated vinyl cations are key intermediates of the reaction. A bidirectional approach provided selective access to the angular annulated product in high yield, which was explained by calculations.

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Section: Methodsmentioning

confidence: 99%

On the Gold‐Catalyzed Generation of Vinyl Cations from 1,5‐Diynes

et al. 2017

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“…1,2-Bis(phenylethynyl)benzene (1). 1,2-Dibromobenzene (1.21 mL, 10 mmol) was coupled to phenylacetylene (3.29 mL, 30 mmol) as described above using copper(I) iodide (0.23 g, 1.2 mmol), bis(triphenylphosphine)palladium(II) dichloride (0.42 g, 0.6 mmol), benzene (5 mL), and triethylamine (8.5 mL, 60 mmol) in a screw cap tube that was then sealed with a Teflon screw cap. The reaction mixture was stirred at 60 °C for 1 day.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Testing of Nonhalogenated Alkyne-Containing Flame-Retarding Polymer Additives

Morgan

Tour

1998

Macromolecules

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In this paper, the synthesis and thermal properties of several alkyne-containing materials are discussed. The materials were synthesized using palladium/copper-or palladium/zinc-mediated crosscoupling reactions between multibrominated aromatics and phenylacetylene. Therefore, in one step, commercially available brominated flame retardants can be converted into nonhalogenated high-char materials using transition metal catalysis. The materials synthesized included polymers, oligomers, carbonates, and diphenyl ethers. The thermal properties of the synthesized materials were studied using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). In general, the DSC and TGA data showed that the synthesized materials were all high-char-yielding materials. Further, DSC data showed that the materials which had o-dialkyne substitutions (enediyne systems) generally cross-linked at lower temperatures than materials that had m-dialkynes. However, TGA showed that the materials with ortho substitutions, especially those with multiple ortho substitutions, generally had higher char yields than those with meta substitutions. The materials were blended into polycarbonate and tested for ignition resistance using the UL-94 flame test. Alkyne-containing oligomer 9, used in conjunction with 0.5 wt % of a bromide-containing flame retardant, provided flame retardancy in polycarbonate according to the UL-94 test. This indicates that alkyne-containing materials, acting as condensed phase flame retardants, can substantially lower the amount of halogen content needed for flame retardancy in polycarbonate.

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“…While 2-(phenylethynyl)napthalene forms slowly the two expected ketones in equal amounts (Table 1, entry 6), the more hindered 1-(phenylethynyl)naphthalene does not react at all under the same conditions. Likewise, 9-(phenylethynyl)-phenanthrene [16] and 1,2-bis(phenylethynyl)benzene [17] proved inactive.…”

Section: Dependence On the Substratementioning

confidence: 97%

Further studies on hydration of alkynes by the PtCl4–CO catalyst

Israelsohn

Vollhardt

Blum

2002

Journal of Molecular Catalysis A: Chemical

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Dedicated to Professor Myron Rosenblum on the occasion of his 75 th birthday in recognition of his outstanding contribution to chemistry AbstractUnder CO atmosphere, between 80 and 120˚C, a glyme solution of PtCl 4 forms a carbonyl compound that promotes hydration of internal as well as terminal alkynes to give aldehyde-free ketones. The catalytic process depends strongly on the electronic and steric nature of the substrates. Part of the carbonyl functions of the catalyst can be replaced by phosphine ligands. Chiral DIOP reacts with the PtCl 4 -CO compound to give a catalyst that promotes partial kinetic resolution of a racemic alkyne. Replacement of part of the CO by polystyrene-bound diphenylphosphine enables to attach the catalyst to the polymeric support. Upon entrapment of the platinum compound in a silica sol-gel matrix, it reacts as a partially recyclable catalyst. A reformulated mechanism for the PdCl 4 -CO catalyzed hydration is suggested on the basis of the present study.

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Cyclo-oligomerization and rearrangement of some phenylated diynes by the RhCl3Aliquat 336 and by the H2PtCl6Aliquat 336 catalysts under phase transfer conditions

Cited by 35 publications

References 16 publications

On the Gold‐Catalyzed Generation of Vinyl Cations from 1,5‐Diynes

On the Gold‐Catalyzed Generation of Vinyl Cations from 1,5‐Diynes

Synthesis and Testing of Nonhalogenated Alkyne-Containing Flame-Retarding Polymer Additives

Further studies on hydration of alkynes by the PtCl4–CO catalyst

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