A Simple Synthesis of Stable Heterocyclic Phosphorus Ylides Derived from NH-Acids

Crystalline phosphorus ylides are obtained in excellent yields from the addition reaction between triphenylphosphine, dimethyl acetylenedicarboxylate and strong NH-acids, such as 2-acetylpyrrole, indole, ethyl 3-indolylglyoxalate and N -benzyl-2-pyrrolylglyoxamate. Dynamic NMR effects are observed in the 1 H NMR spectra of stabilized ylides obtained from 2-acetylpyrrole and indole ( j G p = 67.1 and 68.8 kJmol m 1 respectively) and are attributed to restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

An Efficient Synthesis of Stable Phosphorus Ylides Derived from Hydantoin and 5,5-dialkylhydantoins

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of strong NH-acids, such as hydantoin and 5,5-dialkylhydantoins. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

One-Pot Synthesis of Stable Phosphorus Ylides Using CH-Acid Compounds

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and di-tert-butyl acetylendicarboxylate, in the presence of antron, dimedone, indandion, and 3,5-dimethylbarbituric acid. These stable ylides exist in a solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

A Facile One-Pot Synthesis of Highly-Functionalized Stable Heterocyclic Phosphorus Ylides in Aqueous Media

Phthalimide or succinimide undergo a reaction with dialkyl acetylenedicarboxylates and triphenylphosphine to produce highly-functionalized stable heterocyclic phosphorus ylides in good yields in water-tetrahydrofuran (6:1). This methodology is of interest because of the use of water as solvent, thus minimizing the cost, operational hazards, and environmental pollution.     

Synthesis of Dimethyl 2-(2,4,6-Trimethylphenoxy)-3-triphenylphosphoniobutanedioate and its Application in Intramolecular Wittig Reactions

Protonation of the reactive 1:1 intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2,4,6-trimethylphenol leads to a stable ylide in high yield, which is employed in intramolecular Wittig reactions.     

Efficient,Simple Synthesis of Stable Phosphorus Ylides Derived from 4-Aryl Urazoles

Crystalline phosphorus ylides are obtained in nearly quantitative yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates, and 4-aryl urazoles.     

A Simple Synthesis of Stable Phosphoranes Derived from Imides or Acetanilide Derivatives

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates, and strong NH-acids, such as acetanilide, 4-methylacetanilide, 2-cyanoacetanilide, 4-bromoacetanilide, 4-methoxyacetanilide, succinimide, malimide, or phthalimide. These stabilized phosphoranes exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

Triphenylphosphine-Catalyzed Simple Synthesis of Vinyl-Substituted Saccharins

Saccharin (1,1-dioxo-1,2-dihydro-1 u 6 -benzo[ d ]-isothiazol-3-one) undergoes a smooth reaction with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine to produce highly-functionalized salt-free sulfur-containing ylides in nearly quantitative yields. These stabilized phosphorus ylides exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. These ylides are converted to dialkyl 2-(1,1-dioxo-1 H -1 u 6 -benzo[ d ]-isothiazol-3-yl)-but-2-enedioates in boiling toluene.     

Three-Component Reaction for an Efficient Synthesis of Stable Phosphorus Ylides Using Mercapto Compounds

Stabilized phosphorus ylides were obtained from the three-component reaction between dialkyl acetylenedicarboxylate and sulfur compounds such as pyridine-2-thione, 2-furylmethanethiol, ethanedithioamide, and N-phenyl-1,2,4-triazole-3-thiol in the presence of triphenylphosphine in excellent yields.     

Triphenylphosphine-Catalyzed Simple Synthesis of Dimethyl 1-Aryl-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylates

Ethyl 2-arylamino-2-oxo-acetates undergo a complex reaction with dimethyl acetylenedicarboxylate in the presence of triphenylphosphine to produce dimethyl 1-aryl-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylates in good yields. Dynamic NMR study of dimethyl 1-(2-methylphenyl)-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylate shows a fairly high energy barrier ( j G p = 53.2 kJmol m 1 ) for rotation around the N-aryl single bond, which leads to an observable atropisomerism.     

An Efficient Synthesis of Stable Sulfur-Containing Phosphoranes Derived from 1-Methylimidazole-2-thiol

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of 1-methylimidazole-2-thiol. These sulfur-containing phosphoranes exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. Using dibenzoylacetylene as Michael acceptor, yields 2-[1-methyl-1 H -imidazole-2-yl)sulfanyl]-1,4-diphenyl-butane-1,4-dione.     

Phosphorus Ylides in the Coordination Sphere of Transition Metals: An Inventory

Phosphorus ylides are not only classical reagents in organic chemistry, but also play an increasingly important role as novel components in organometallic compounds. These metallic “ylide complexes” are either synthesized from “preformed ylides” and coordination compounds by addition or substitution, on the building block principle, or they are formed, in sometimes complicated reactions, from phosphanes, metal complexes, and C₁ substrates in the coordination sphere of the metals. The resulting metal-carbon bonds are greatly modified in their properties by the immediate presence of the phosphonium center and often belong to the most stable of M-C structural units. The metal can come from any group of the periodic table, including the lanthanoids and actinoids. Numerous preparative and structural studies are gradually enabling us to gain an overall picture of the scope of this area of research.     

Three-Component Reaction of Triphenylphosphine,Dimethyl Acetylenedicarboxylate,and Aldehyde Benzoylhydrazones: An Efficient One-Pot Synthesis of Stable Phosphorus Ylides

Protonation of the reactive 1:1 intermediate produced in the reaction between dimethyl acetylenedicarboxylate and triphenylphosphine by benzoylhydrazones leads to vinylphosphonium salts, which undergo Michael addition with the conjugate base of the NH acid to produce highly fanctionalized, salt-free phosphorus ylides in excellent yields.     

Introduction of a Novel Reaction of Triacetylmethane: One-Pot Synthesis of Dialkyl-2-(3,1-hydroxyethylidene-2,4-pentanedione-3-yl)-3-(triphenylphosphoranylidene)-butanedioate

Protonation of reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by 3-(1-hydroxyethylidene)-2,4-pentanedione leads to vinyl phosphonium salts, which undergo Michael addition with the conjugate base of CH-acid to produce the title compounds in high yield.     

A Simple Synthesis of Stable Phosphorus Ylides from Indole and Some of Its Derivatives

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of strong NH acids, such as indole and 2-methyl indole, 3-methyl indole, and 5-boromo indole. These stable ylides exist in a solution as a mixture of two geometrical isomers as a result of the restricted rotation around the carbon–carbon partial double bond resulting from the conjugation of the ylide moiety with the adjacent carbonyl group.     

A Simple Synthesis of Stable Phosphorus Ylides Derived from 2-Benzoxazolinone and 2-Mercaptobenzoxazole

The reaction of triphenylphosphine with dialkyl acetylenedicarboxylates in the presence of a strong SH-acid or NH-acid, such as 2-mercaptobenzoxazole and 2-benzoxazolinone, has been studied. In some cases, stable phosphorus ylides are obtained in excellent yields. The ylide moiety of these compounds is strongly conjugated with the adjacent carbonyl group, and the rotation about the partial double bond in (E) and (Z) geometrical isomers is slow on the NMR time scale at an ambient temperature. Thus, these exist as a mixture of geometrical isomers.     

Vinylphosphonium Salt Mediated One-Pot Stereoselective Synthesis of Dialkyl 3,3-Diacetyl-3 a -hydroxy-8-oxo-2,3,3 a ,8-tetrahydrocyclopenta-[ a ]indene-1,2-dicarboxylates

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine (or tributylphosphine) and dialkyl acetylenedicarboxylates by acetylacetone leads to sterically congested phosphorus ylides, which undergo an intermolecular Wittig reaction with ninhydrin and concomitant annulation in CH 2 Cl 2 at room temperature to produce dialkyl 3,3-diacetyl-3 a -hydroxy-8-oxo-2,3,3 a ,8-tetrahydrocyclopenta[ a ]indene-1,2-dicarboxylates in fairly high yields.     

An Efficient One-Pot Synthesis of Triamides and Amidodiesters

An efficient one-pot procedure has been proposed for the synthesis of compounds containing three carboxamide groups or one carboxamide and two ester groups. The procedure is based on three-component condensation of alkyl isocyanides with 5-alkylidene- or 5-arylmethylene-substituted Meldrum's acids in the presence of such nucleophiles as phenols and amines.     

A Facile Synthesis of Stable Phosphorus Ylides Containing Chlorine and Sulfur Derived from 6-Chloro-2-benzoxazolethiol and 2-Chloro-phenothiazine

Stable crystalline phosphorus ylides containing chlorine and sulfur were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylene-dicarboxylates in the presence of 6-chloro-2-benzoxazolethiol and 2-chloro-phenothiazine. These stable ylides exist in solution as a mixture of two geometrical isomers. This is caused by the conjugation of the ylide moiety with the adjacent carbonyl group, which results in a restricted rotation around the respective carbon-carbon bond.