Reactions of 1-alkynylphosphonates with group (IV) complexes

Al-Quntar, Abed Al-Aziz; Srebnik, Morris

doi:10.1016/j.jorganchem.2004.10.029

Cited by 15 publications

(2 citation statements)

References 77 publications

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“…19 Over the past few years we have been investigating the conversion of 1-alkynylphosphonate to highly substituted vinylphosphonates with group IV reagents. 20 We have shown that the intermediate metallocycles are very sensitive to the reaction conditions. Various substituted vinylphosphonates can be obtained from the same electrophile by changing both the quantities of reagents required to generate the reactive group IV species and the metal additives.…”

Section: Introductionmentioning

confidence: 94%

Direct Cyclopropanation of 1-Alkynylphosphonates by Cp₂ZrCl₂/2EtMgBr/2AlCl₃ To Afford Cyclopropylmethylphosphonates

Quntar

Srebnik

2005

J. Org. Chem.

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[reaction: see text] The reagent system Cp2ZrCl2/2EtMgBr/2AlCl3 converts 1-alkynylphosphonates into cyclopropylmethylphosphonates 3 in good isolated yields. Ethers, chlorides, and other cyclopropyl groups are compatible with the reaction conditions. Deuterium labeling is consistent with the formation of stable cyclopropylmethylbimetallic phosphonates by ring contraction of the corresponding aluminacyclopentenylphosphonate. Temperature is crucial; apparently, the cyclopropylmethylbimetallic phosphonates are in equilibrium with the aluminacyclopentenylphosphonates. Low temperature favors the former. We surmise that the negative charges of the intermediate are stabilized by the phosphonate group. Thus, diphenylacetylene and 3-hexyne failed to give cyclopropyl products under the same reaction conditions.

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Section: Introductionmentioning

confidence: 94%

Direct Cyclopropanation of 1-Alkynylphosphonates by Cp₂ZrCl₂/2EtMgBr/2AlCl₃ To Afford Cyclopropylmethylphosphonates

Quntar

Srebnik

2005

J. Org. Chem.

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“…[47] They are also useful for the synthesis of 2-(aryl)vinylphosphonates through direct Heck coupling reactions with aryl halides. [48] In spite of a wide range of reports for the synthesis of internal vinylphosphonates, [49][50][51][52][53][54] only noncoherent and scattered studies have been conducted on the synthesis of terminal vinylphosphonates. [55][56][57] The sporadic reported procedures suffer from some drawbacks such as low yield of the products, long reaction times, inefficient recovery and recycling of the catalyst and limit to only a few examples.…”

Section: Introductionmentioning

confidence: 99%

One-pot Synthesis of Terminal Vinylphosphonates Catalyzed by Pyridine Grafted GO as Reusable Acid-Base Bifunctional Catalyst

Sobhani

Zarifi

2016

ChemistrySelect

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Pyridine grafted graphene oxide (Py‐GO) as an acid‐base bifunctional catalyst was found to show cooperative catalysis in the one‐pot synthesis of vinylphosphonates. In the presence of this catalyst, a variety of vinylphosphonates were synthesized by the reaction of different aldehydes (aryl, heteroaryl and alkyl aldehydes), phosphite esters and nitromethane in water. The present method is the first report for the one‐pot synthesis of terminal vinylphosphonates using a reusable heterogeneous catalyst through a cascade Henry‐Michael reaction followed by nitro elimination. This protocol offers several advantages such as using a simplified one‐pot synthetic process with step saving, the least amount of waste, and low operational cost. Furthermore, the heterogeneous catalyst was successfully recovered and reused five times with unaltered catalytic activity.

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