Vinylphosphonium Salts Research Articles

Vinylphosphonium Salt Mediated Efficient Synthesis of Dialkyl 1H-Pyrrolizine-2,3-dicarboxylates

Protonation of the 1:1 intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by pyrrole-2-carbaldehyde leads to a vinylphosphonium salt, which undergoes intramolecular Wittig reaction to produce the title compounds in good yields.

Stereoselective Synthesis of Tetraalkyl Cyclobutene-1,2,3,4-tetracarboxylates. Synthesis of Tetraalkyl (Z,Z)-Buta-1,3-diene-1,2,3,4-tetracarboxylates

Tetraalkyl cyclobutene-1,2,3,4-tetracarboxylates, prepared by intramolecular Wittig reaction between a vinylphosphonium salt and diethyl 2-oxobutanedioate, undergo electrocyclic ring-opening reactions, in boiling toluene, to produce highly electron-deficient 1,3-dienes.

Vinylphosphonium Salt Mediated Efficient Synthesis of Dialkyl 1H-Pyrrolizine-2,3-dicarboxylates

Protonation of the 1:1 intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by pyrrole-2-carbaldehyde leads to a vinylphosphonium salt, which undergoes intramolecular Wittig reaction to produce the title compounds in good yields.

Vinylphosphonium salt mediated stereoselective synthesis of cyclobutene derivatives. A facile route to highly electron-deficient 1,3-dienes

Ethyl 4-aryl-2,4-dioxobutanoates undergo stereoselective intramolecular Wittig reaction with a vinyltriphenylphosphonium salt to yield cyclobutene derivatives, which undergo electrocyclic ring-opening reactions in boiling toluene to produce highly electron-deficient 1,3-dienes.

5(4 H)-Oxazolones. Part XI. Cycloaddition reaction of oxazolones and münchnones to triphenylvinylphosphonium salts as synthetic equivalents of alkynes

5(4 H)-Oxazolones 1 and münchnones 3 are reacted with triphenylvinylphosphonium bromide 2a to give, through a cycloaddition reaction, pyrrole derivatives 4a-d and 7a-c unsubstituted at C-3 and C-4. The use of substituted vinylphosphonium salts 2b,c and dipoles 1 and 3 allows the isolation of 3-methylpyrroles 4e,f and 7d,e and 3-pyrrolecarboxylic acids 9a-c, respectively. The cycloaddition reactions proceed with high regioselectivity because of the positive interaction of phosphonium group of 2 and carbonyl group of dipoles 1 and 3.

New Synthesis of Tetraalkyl 2,3-Dihydro-5-oxopyrrolo[2,1-a]isoindole-1,2,3,3-tetracarboxylates and Tetraalkyl 2,3-Dihydro-5-oxopyrrolo[2,1-a]pyrrolidine-1,2,3,3-tetracarboxylates Mediated by Vinyltriphenylphosphonium Salts

Protonation of the reactive 1:1 intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by CH-acids, such as dialkyl phthalimidomalonates and dimethyl succinimidomalonate, leads to a vinylphosphonium salt, which undergoes intramolecular Wittig reaction to produce the title compounds in fairly high yields.

Vinylphosphonium Salts and Allenes from Carbonyl Compounds Using Titanium-Substituted Ylides.

(E)-Vinylphosphonium salts are conveniently obtained from the reaction of carbonyl compounds with titanium-substituted ylide species (Me(2)N)(3)P=CHTi(OiPr)Cl(2) or (Me(2)N)(3)P=CHTi(OiPr)(2)Cl. While a wide variety of nonenolizable aldehydes are tolerated, the steric bulk surrounding the ylide carbon limits the process to highly activated or unhindered ketones. The vinylphosphonium salts may be converted to allenes by deprotonation and condensation with a second aldehyde, thus accomplishing a two-step double olefination allene synthesis. This methodology, along with a previously reported one-pot reaction, comprises the most convenient route available for the synthesis of 1,3-disubstituted allenes. The metal-substituted ylide reagent may be generated in situ from commercially-available starting materials. Two representative vinylphosphonium salts were shown to undergo reversible isomerization to the (Z)-form upon irradiation.

The Mechanism of Double Olefination Using Titanium-Substituted Ylides.

The adduct 3, derived from TiCl(3)(OiPr) and (Me(2)N)(3)P=CH(2), engages in a complicated set of interactions with NaN(SiMe(3))(2) and aldehydes, resulting in the requirement to use excess amounts of both reagents for the one-pot synthesis of allenes. When TiCl(2)(OiPr)(2) is used instead, ligand substitution reactions with NaN(SiMe(3))(2) are diminished and so stepwise transformations can be accomplished without excess amounts of each reagent. The selective production of vinylphosphonium salts and byproduct titanium oxides from Ti-substituted ylides and aldehydes is proposed to arise from the presence of a chloride leaving group on the metal. Isolated vinylphosphonium compounds may be deprotonated with phenyllithium to give thermally sensitive allenic phosphoranes, which have been characterized by low temperature multinuclear NMR. The reaction of allenic phosphoranes with aldehydes affords oxaphosphetane and betaine intermediates which appear to interconvert upon warming to produce allene and phosphine oxide. Dimethylamino-substituted phosphorus components are required for high yields in both steps of the allene-forming process, presumably to boost the reactivity of the hindered Ti-substituted ylide reagents and to stabilize the allenic phosphorane unit so that it may be trapped by aldehyde. The placement of chiral groups on the phosphorus methylide or aldehyde components results in low levels of enantiomeric and diastereomeric induction, respectively, during allene formation. In two cases, the diastereomeric ratios of initially-formed oxaphosphetanes have been found to differ from the diastereomeric composition of their product allenes, offering examples of the phenomenon known as "stereochemical drift". However, oxaphosphetane/betaine formation from allenic phosphorane and aldehyde has been found to be irreversible, suggesting that an intramolecular betaine olefin isomerization is responsible for the loss of stereochemical integrity during the Wittig step.

ChemInform Abstract: Reaction of Vinylphosphonium Salts with Sulfoxonium Ylides. Synthesis of Cyclopropylphosphonium Salts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of Vinylphosphonium Salts with Sulfoxonium Ylides. Synthesis of Cyclopropylphosphonium Salts

Abstract Reactions of (dimethylamino)phenylsulfoxonium methylide with triphenylvinylphosphonium salts gave the corresponding cyclopropyltriphenylphosphonium salts (E-form) in high yields, when 1,8-diazabicyclo[5.4.0]undec-7-ene was used as a base. Reactions of cyclopropyltriphenylphosphonium salts with sodium hydride in the presence of tris[2-(2-methoxyethoxy)ethyl]amine afforded the corresponding ylides, which further reacted with aldehydes to give alkylidenecyclopropanes in high yields.

Structure and properties of phosphonium ylides obtained by the reaction of 3-phosphorylated 1,4-dichloro-2-aza-1,3-dienes with sodium azide

The substituted vinylphosphonium salts of the general formula RCClC (NCClAr)P +Ph 3 Cl − react with an excess of sodium azide in a peculiar manner. As a result, phosphonium ylides are produced. They are stabilized with a nitrile and a 5-aryltetrazol-1-yl group or with two substituted tetrazolyl residues as confirmed by X-ray structural analysis. All the ylides obtained exhibit low reactivity and do not enter into the Wittig reaction, but one of them was found to undergo the following sequence of transformations: NC C P(⧸)(⧹) → H 2NCO C P(⧸)(⧹) → (⧹) (⧸)PNCOCH 2.

Reaction of Olefins with Dimethyl(methylthio)sulfonium Salts in the Presence of Triphenylphosphine. Preparation of Vinylphosphonium Salts

Abstract Olefins were effectively converted into the corresponding (2-methylthioalkyl)triphenylphosphonium salts by the reaction with dimethyl(methylthio)sulfonium salts in the presence of triphenylphosphine. 2-Triphenylphosphonioalkyldimethylsulfonium salts, synthesized by alkylation of the corresponding methylthiophosphonium salts, react with 1,8-diazabicyclo[5.4.0]undec-7-ene or aq NaOH to afford the corresponding vinylphosphonium salts or vinylphosphine oxides in good yields.

ADDITIONS OF NUCLEOPHILES TO VINYL PHOSPHONIUM SALTS. A USEFUL WAY TO OBTAIN NEW SYNTHONS

Abstract The vinylphosphonium salts 2. obtained from allenyl compounds 1. are phosphorus synthetic equivalents of γ functionalized allylic carbocations. Nucleophilic addition reactions give polyfunctional phosphonium salts, useful starting materials for further investigations. As a function of the basicity of the nucleophile, the addition reaction is in competition with elimination of the phosphorus group in 2, leading to reformation of the allenic starting material 1.

Reverse microemulsions mediated synthesis of vinylphosphonium salts.

PPH 3 reacts with activated alkynes in reverse (water-hydrocarbon) microemulsions giving specifically rise to a mixture of Z and E triphenylvinylphosphonium salts which are readily isolated in good yields.

Reaction of stannyl-substituted phosphorus ylides with boron trifluoride diethyl etherate: evidence for formation of transient triphenylphosphonio-substituted stannaethenes

The reaction of the stannyl-substituted phosphorus ylide Ph 3 PCH(SntBu 2 OiPr) (4) with boron trifluoride diethyl etherate yields [1,1,3,3-Tetra-tert-butyl-2,4-bis(triphenylphosphonio)-1,3-distannetane] bis(tetrafluoroborate) (11) in addition to Ph 3 PCH 2 SntBu 2 F + BF 4 − (12) and boranyl-substituted phosphorus ylides (13). A different reactivity is shown by the ylide Ph 3 PCCH 3 5SntBu 2 OiPr) (5), which reacts with boron trifluoride diethyl etherate with formation of a betaine, Ph 3 PCCH 3 (BF 3 )(SntBu 2 F) (22). If benzophenone is added as trapping reagent, reduction to diphenylcarbinol, Ph 2 CHOH, is observed and the vinylphosphonium salt Ph 3 P + (C=CH 2 )SntBu 2 FBF 4 − (23) is isolated. The reaction behavior of the assumed transient stannavinylphosphonium salts finds parallels in the well-known reactivity of silaethenes. The X-ray structures (12), (23), (11) are reported

ChemInform Abstract: Vinylphosphonium Salts: Stereoselective Palladium‐Catalyzed Vinylation of Triphenylphosphine with Vinyl Triflates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Organic Chemistry in Water. Part 5. Nucleophilic Addition of Water‐Soluble Phosphines on Activated Alkynes: An Efficient Synthesis of New Vinylphosphonium Salts and of Specifically Deuterated Olefins.

AbstractThe hydrophilic phosphines (I) and (V) react in water with a variety of activated alkynes (9 examples given with tabulated results) affording new vinylphosphonium salts or vinylphosphine oxides as demonstrated for the examples in the scheme.

Vinylphosphonium salts: stereoselective palladium-catalyzed vinylation of triphenylphosphine with vinyl triflates

The reaction of vinyl triflates with a slight excess of triphenylphosphine and 1-3 mol% Pd(PPh 3 ) 4 in refluxing THF results in the formation of the corresponding vinyltriphenylphosphonium triflate salts in good yield. A wide variety of salts, including cyclic ones, can be prepared

ChemInform Abstract: Reaction of Olefins (I) with Dimethylthiomethylsulfonium Salts (II) and Triphenylphosphine (III). A New Convenient Synthesis of Vinylphosphonium Salts.

ChemInform Abstract: Reaction of Olefins (I) with Dimethylthiomethylsulfonium Salts (II) and Triphenylphosphine (III). A New Convenient Synthesis of Vinylphosphonium Salts.

Organic chemistry in water (part v) Nucleophilic addition of water-soluble phosphines on activated Alkynes : an efficient synthesis of new vinylphosphonium salts and of specifically deuterated olefins

Triphenylphosphinc m-trisulfonate [P(mC 6H 4S0 3Na) 3 =TPPTS]1 and triphenylphosphine m-monosulfonate [Ph 2P(mC 6H 4SO 3Na)=TPPMS]2 react in water with activated alkynes R-C s C-A (A = CO 2H, CO 2R l, COR 2, CHO) affording new vinylphosphonium salts or vinylphosphine oxides or alkenes depending on the pH of the aqueous solution and on the nature of the substituent R. The reactions of 1 or 2 with alkynes bearing an electron-acceptor substituent R give rise to the corresponding trans disubstituted olefins. Specifically mono or dideuterated alkenes are thus obtained in good yields by sequential use of H 2O-D 2O. When R = H or Alkyl, vinylphosphonium salts or vinylphosphine oxides are quantitatively produced respectively in acidic or in neutral medium