A new route to stabilized ylides: A one-pot polyene synthesis

Vedejs, E.; Bershas, James P.

doi:10.1016/s0040-4039(00)72142-3

Cited by 35 publications

(6 citation statements)

References 10 publications

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“…Evaporation of the toluene afforded a crude product, which was purified by means of silica gel column chromatography in diethyl ether. The oil obtained was compound (5a) (1.0 3579,199 (26), 116 (28), 89 (26), and 55 (100).…”

Section: -Ethoxycarbonyl-4-phenyl-1 -(2-thienyl)-2-azabuta-13-diene (3c)mentioning

confidence: 99%

Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Barluenga¹,

Ferrero²,

Palacios³

1990

J. Chem. Soc., Perkin Trans. 1

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The reactivity of the P=N double bond of the N-vinylic h5-phosphazene (1) towards several electrophiles is reported. Intermolecular aza-Wittig reaction of Wphosphazene (1 ) with aldehydes, phenyl isocyanate, and acid anhydrides leads to ethoxycarbonyl 2-aza-l,3-dienes (3), conjugated carbodi-imides (4), and N-protected amino acrylic acid derivatives ( 5 ) , respectively, while the Z-azahexa-l,3,5-triene (8) and also the pyridine (7) are obtained when dienyl h5-phosphazenes (6) are used. Reaction of h5-phosphatene (1) with methyl iodide and acetyl chloride leads t o N-alkylated (10) and N-acylated derivatives (11 ), respectively. Treatment of compound (1 1 ) in the presence of amino derivatives affords 1 -amino-2-azabuta-l,3-dienes (14).

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Section: -Ethoxycarbonyl-4-phenyl-1 -(2-thienyl)-2-azabuta-13-diene (3c)mentioning

confidence: 99%

Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Barluenga¹,

Ferrero²,

Palacios³

1990

J. Chem. Soc., Perkin Trans. 1

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“…The solvents and reagents employed were freshly distilled from the following materials: benzenepotassium metal; acetonitrile -phosphorus pentoxide; triethylamine and tetrahydrofuran (THF) -lithium aluminum hydride; hexamethylphosphoramide (HMPA) and diisopropylaminecalcium hydride. (Table I , Entries 1,3,7,9, IZ) To an ice-cold, stirred solution of recrystallized triphenylphosphine (576mg, 2.2mmol) in 20mL of dry benzene was added 3.7 mL of a 0.6 M solution of chlorine in carbon tetrachloride. After the addition was complete, tlc analysis of the mixture indicated that triphenylphosphine was absent.…”

Section: Generalmentioning

confidence: 99%

“…To a stirred solution of recrystallized triphenylphosphine (576mg, 2.2mmol) in 20mL of dry acetonitrile was added 559 mg (2.2 mmol) of iodine and the mixture was stirred at room temperature for 2 h. To the resulting orange-yellow suspension was added successively triethylamine (220 mg, 2.2 mmol) and the appropriate P-diketone (2.0 mmol). The mixture was either stirred at room temperature for 4 days (Procedure B, Table 3, Entries 2,5,7,10) or was heated at reflux temperature for the indicated length of time (Procedure C, Table 3. Entries 3,6,8,11,13).…”

Section: General Procedures For the Concersion Of P-diketones Into B-cmentioning

confidence: 99%

“…Indeed, it was found that reaction of various P-diketones with triphenylphosphine diiodidetriethylamine in dry acetonitrile at room temperature (Procedure B) produced directly improved yields of the corresponding P-iodo enones ( Table 3, Entries 2,5,7,10). However, even when this polar solvent was used, the reactions at room temperature were slow and, typically, reaction times of -4 days were required for complete conversion of the product provided spectral data consistent with that expected for 3-iodo-6-methyl-2-cyclohexen-1-one (45), while the minor component was shown on the basis of the infrared and 'H nmr spectra to consist of a mixture of the isomeric iodo ketones 53 and 61 (ratio ~8 : 3 , respectively).…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of β-chloro, β-bromo, and β-iodo α,β-unsaturated ketones

Piers¹,

Grierson²,

Lau³

et al. 1982

Can. J. Chem.

105

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EDWARD PIERS, JOHN R. GRIERSON, CHEUK KUN LAU, and ISAO NAGAKURA. Can. J. Chem. 60,210 (1982). A new, efficient method for the preparation of P-chloro, P-bromo, and P-iodo a$-unsaturated ketones is described. The method involves the reaction of P-diketones or a-hydroxymethylenecycloalkanones with triphenylphosphine dihalides in the presence of triethylamine. With the dichloride and dibromide reagents, the reactions are conveniently carried out in benzene at room temperature, while with triphenylphosphine diiodide the reactions are best performed in refluxing acetonitrile (P-diketones) or in acetonitrile-hexamethylphosphoramide (a-hydroxymethylenecycloalkanones). The reaction of triphenylphosphine diiodide -triethylamine with a series of 4-alkyl-l,3-cyclohexanediones provides mainly or exclusively (depending on the size of the alkyl group) 6-alkyl-3-iodo-2-cyclohexen-I-ones, while reaction of this reagent with 2-hydroxymethylenecyclohexanone and 2-hydroxymethylenecyclopentanone affords stereoselectively and regioselectively (E)-2-iodomethylenecyclohexanone and (E)-2-iodomethylenecyclopentanone, respectively. On decrit une nouvelle methode efficace de preparatton des P-chloro, P-bromo et P-iodo cetones a,P-insaturees. La methode fait intervenir la reaction des P-dicetones ou des a-hydroxymethylenecycloalcanones avec les dihaiogenures de triphenylphosphine en presence de triethylamine. Les reactions ont lieu dans le benzene a la temperature ambiante si on utilise les dichlorures ou les dibromures comme reactifs, tandis qu'avec le diiodure de triphenylphosphine, on obtient de meilleures reactions dans I'acetonitrile au reflux (P-dicetones) ou dans un melange d'acetonitrile-hexamethylphosphoramide (a-hydroxymethylenecycloalcanones). La reaction du diiodure de triphenylphosphine dans la triethylamine avec une serie d'alkyl-4 cyclohexanediones-l,3 conduit principalement ou exclusivement (dependant de la taille du groupe alkyle) aux alkyl-6 iodo-3-cyclohexen-2 ones-1, tandis que ce m6mereactif avec I'hydroxymethylene-2 cyclohexanone et I'hydroxymethylene-2 cyclopentanone conduit de f a~o n stereoselective et regioselective aux iodomethylene-2 cyclohexanone-(E) et iodomethylene-2 cyclopentanone-(E) respectivement. EDWARD PIERS, JOHN R. GRIERSON, CHEUK KUN LAU[Traduit par le journal] Introduction chloride (39), oxalyl chloride (40, 9), and triphenyl-P-Chloro a,P-unsaturated ketones have been phosphine -carbon tetrachloride (41). Of these, known for a long time (1) and, over the years, have the latter two reagents appear to be the best in served as important and versatile intermediates in terms of c~n~e n i e n~e and efficiency. Con~erSion of organic On the other hand, the corre-P-diketones into P-bromo enones has traditionally sponding bromo compounds, although known, do been accomplished by treatment of the not appear to have been used a great deal by substrates with phosphorus tribromide (29,36,42), synthetic organic chemists. Furthermore, prior to although the yield of this Process does not appear to the initiation of ...

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“…This strategy also appeared attractive since it would potentially allow control of the double bond geometry at both olefinic sites . It might be noted that we had some initial concerns regarding the possibility that a keto phosphonate such as 3 , or one of its synthetic precursors, might be prone to undergo facile elimination of HCl and/or ROH or to 1,4-addition/elimination processes . In this note we report that this type of Wadsworth−Emmons−Horner synthon can in fact be easily prepared and smoothly undergoes the desired stereoselective coupling with aldehydes.…”

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confidence: 94%

Studies on the Synthesis of Pinnaic Acid and Halichlorine. Stereoselective Preparation of a (Z)-δ-Chloro-γ,δ-unsaturated-β-keto Phosphonate as a Side Chain Synthon

Keen

Weinreb

1998

J. Org. Chem.

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A new route to stabilized ylides: A one-pot polyene synthesis

Cited by 35 publications

References 10 publications

Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Synthesis of β-chloro, β-bromo, and β-iodo α,β-unsaturated ketones

Studies on the Synthesis of Pinnaic Acid and Halichlorine. Stereoselective Preparation of a (Z)-δ-Chloro-γ,δ-unsaturated-β-keto Phosphonate as a Side Chain Synthon

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A new route to stabilized ylides: A one-pot polyene synthesis

Cited by 35 publications

References 10 publications

Reactivity and selectivity of N-vinylic λ5-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Reactivity and selectivity of N-vinylic λ5-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Synthesis of β-chloro, β-bromo, and β-iodo α,β-unsaturated ketones

Studies on the Synthesis of Pinnaic Acid and Halichlorine. Stereoselective Preparation of a (Z)-δ-Chloro-γ,δ-unsaturated-β-keto Phosphonate as a Side Chain Synthon

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Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes

Reactivity and selectivity of N-vinylic λ⁵-phosphazenes towards electrophiles. Synthesis of 2-aza-1,3-dienes