Cyclopropanation of alkenes with CH2I2/Et3Al by the phase-vanishing method based on fluorous phase screen

Matsubara, Hiroshi; Tsukida, Masaaki; Yasuda, Shinji; Ryu, Ilhyong

doi:10.1016/j.jfluchem.2008.06.004

Cited by 16 publications

(6 citation statements)

References 15 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Phase-vanishing (PV) reactions are triphasic reactions, which involve a reagent, a liquid perfluoroalkane, and a substrate. − The perfluoroalkane, which is in the layer between the two, acts as a phase screen. It is inert and is used to separate the reactants.…”

mentioning

confidence: 99%

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Zee

Dragojlović

2009

Org. Lett.

View full text Add to dashboard Cite

Phase-vanishing reactions are triphasic reactions, which involve a reagent, a liquid perfluoroalkane, and a substrate. In a phase-vanishing reaction with PTFE tape as the phase screen instead of a liquid perfluoroalkane, there is no limitation related to the density of a phase and the denser phase can be in the top layer. The reactions were faster compared to traditional PV reactions, and it was possible to carry out sequential and tandem reactions and reactions under a reflux.

show abstract

mentioning

confidence: 99%

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Zee

Dragojlović

2009

Org. Lett.

View full text Add to dashboard Cite

show abstract

“…Besides the common mechanism involving a bromonium ion as an intermediate, bromination of cis -stilbene may involve the corresponding carbocation [ 24 – 25 ] as well as isomerization, followed by a subsequent bromination of trans -stilbene. Other research groups have been able to improve selectivity of bromination by using tridecylmethylphosphonium tribromide [ 12 ] or pyridinium hydrobromide perbromide [ 23 ]. Still, a considerable amount (10–20%) of the meso -dibromostilbene ( 12 ) was produced.…”

Section: Resultsmentioning

confidence: 99%

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen

Pels¹,

Dragojlovic²

2009

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

SummaryIn a solvent-free phase-vanishing reaction with PTFE (polytetrafluoroethylene, Teflon®) tape as the phase screen, a thermometer adapter is utilized to insert a PTFE-sealed tube into the vapor phase above the substrate. Besides avoiding use of solvents, the experimental design is not dependent upon the densities of the reactants and the procedure generates little or no waste while providing the reaction products in high yield and in high purity.

show abstract

“…After 8 h, two layers resulted; however, the reaction was not yet complete. After vigorous stirring for additional 4 h, the organic phase was collected and purification by silica gel column chromatography gave decylcyclopropane in 98% yield 23…”

Section: Applications Of Pv Methods To Other Reactionsmentioning

confidence: 99%

Phase‐vanishing methods based on fluorous phase screen: A simple way for efficient execution of organic synthesis

Ryu

Matsubara

Nakamura

et al. 2008

The Chemical Record

Self Cite

View full text Add to dashboard Cite

The phase-vanishing (PV) method is based on spontaneous reaction controlled by diffusion of reagents into fluorous media, such as perfluorohexanes (FC-72) and polyperfluoroethers. Thus, the original PV reaction utilizes a triphasic test tube method composed of a bottom reagent phase, a middle fluorous phase, and a top substrate phase. In such a triphasic system, the fluorous phase acts as a liquid membrane to transport the bottom reagents to the top organic phase containing substrates. In the end, the bottom layer disappears and two phases remain. Since the first demonstration of the PV method by bromination of alkenes with molecular bromine, a number of applications have been developed thus far. These include halogenation of alcohols with SOBr(2) and PBr(3), demethylation of methoxyarenes with BBr(3), cyclopropanation of alkenes by CH(2)I(2)-AlEt(3), and Friedel-Crafts acylation of aromatic compounds with SnCl(4). A fluorous triphasic U-tube method is effective for chlorination of alcohols based on lighter (less dense) reagents such as SOCl(2) and PCl(3). A system using a solution containing reagents as a bottom phase is useful for oxidation with m-CPBA, which may be defined as a new category for the "extractive PV" method. Recent advances include a "quadraphasic" PV method, in which an aqueous "scavenger" phase is added to the original triphasic PV method to remove acidic by-products.

show abstract

Cyclopropanation of alkenes with CH2I2/Et3Al by the phase-vanishing method based on fluorous phase screen

Cited by 16 publications

References 15 publications

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen

Phase‐vanishing methods based on fluorous phase screen: A simple way for efficient execution of organic synthesis

Contact Info

Product

Resources

About

Cyclopropanation of alkenes with CH2I2/Et3Al by the phase-vanishing method based on fluorous phase screen

Cited by 16 publications

References 15 publications

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Phase-Vanishing Reactions with PTFE (Teflon) as a Phase Screen

Solvent-free phase-vanishing reactions with PTFE (Teflon®) as a phase screen

Phase‐vanishing methods based on fluorous phase screen: A simple way for efficient execution of organic synthesis

Contact Info

Product

Resources

About

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen