Two new syntheses of the “phospha‐wittig” reagents

Bauer, Siegfried; Marinetti, Angéla; Mathey, François

doi:10.1002/hc.520020209

Cited by 13 publications

(8 citation statements)

References 13 publications

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“…Preparation according to the general procedure: 31.1 g (0.044 mol) of 3a, 4.89 g (0.044 mol) of Me 3 NO•2H 2 O, and 15.48 g (0.044 mol) of tungstenhexacarbonyl. The 31 P NMR of compound 5a has been described in the literature 18 and is consistent with that found by us. Yield: 26.13 g, 84%.…”

Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...supporting

confidence: 90%

“…Depending on the substituent at ■ RESULTS AND DISCUSSION Scheme 2 summarizes three synthetic protocols that are described in the literature for the preparation of phospha-Wittig−Horner reagents. 4,5,18,19 The crucial step of routes (a) and (b) in Scheme 2 involves 2-fold lithiation of the primary phosphine tungsten complex III, which in our hands proved to be difficult. According to 31 P NMR analysis of the reaction mixture, III undergoes only partial lithiation with BuLi or t-BuLi and only at temperatures higher than −20°, irrespective of whether commercial or freshly prepared BuLi was used.…”

Section: ■ Introductionmentioning

confidence: 85%

“…NMR data are consistent with those described in the literature. 18 Yield: 99%. 31 P (CDCl 3 , {H}): 31.3 (d, 1 J P−P = 210.4, P V ), −33.3 (t, P III ).…”

Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...mentioning

confidence: 99%

“…Coordination to the Tungsten Core; General Procedure. (CH 3 CN)W(CO) 5 was prepared in a modified literature procedure: 5,18 1 equiv of Me 3 NO•2H 2 O was added in small portions over 20 min to a suspension of 1 equiv of tungstenhexacarbonyl in acetonitrile. During addition, the reaction temperature was kept below 10 °C.…”

Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...mentioning

confidence: 99%

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Revisiting the Phospha-Wittig–Horner Reaction

2012

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P,P-Dichlorophosphines 2a−c (RPCl 2 , R = Ph (a), t-Bu (b), 2,4,6-Me 3 Ph (c)) and P,P-dibromophosphines 4d,e (RPBr 2 , R = (i-Pr) 3 SiCC (d) and H 2 CCH (e)) react with triethylphosphite under Michaelis−Arbuzov conditions to give phosphinodiphosphonates 3a−e in quantitative yields. After complexation to W(CO) 5 and treatment with CH 3 ONa, phospha-Wittig−Horner reagents 9a,b are obtained on a multigram scale in good overall yield. Phospha-Wittig−Horner reagents with unsaturated substituents at III P (10d,e) can be prepared in analogous procedures; however, they prevail in an unusual ylide form that allows conjugation between the lone pair and the acetylene and vinyl π-systems, respectively. Phosphinophosphonate 9a has been characterized by X-ray crystallography and is shown to react smoothly with acetone within minutes. The resulting W(CO) 5 -coordinated phosphaalkene is shown to dimerize to a 1,2-diphosphitane or to undergo a 1,3-proton shift depending on the reaction conditions. In addition, a one-pot synthetic sequence starting from W(CO) 5 -coordinated phosphinodiphosphonates 5d,e has been developed to engage compounds with vinyl and acetylene substituents in phospha-Wittig−Horner reactions.

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Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...supporting

confidence: 90%

Section: ■ Introductionmentioning

confidence: 85%

“…NMR data are consistent with those described in the literature. 18 Yield: 99%. 31 P (CDCl 3 , {H}): 31.3 (d, 1 J P−P = 210.4, P V ), −33.3 (t, P III ).…”

Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...mentioning

confidence: 99%

Section: R I E T H Y L P H O S P H I T E B I S ( O O -D I E T H Y L...mentioning

confidence: 99%

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Revisiting the Phospha-Wittig–Horner Reaction

2012

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“…Dichlorophosphine (61) and sodium diethylphosphite, in a 1:2 molar ratio, react to furnish product (103) [103].…”

Section: Chemical Properties Of Phosphory-lated Thiophenes 21 Reactmentioning

confidence: 99%

Phosphorylation of Thiophenes

Ivonin¹,

Tolmachev²,

Пинчук³

2008

COC

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This review deals with synthetic methods, chemical transformations, and some physical properties of thienyland benzothienyl substituted phosphorus compounds bearing P-Het or P-CH 2 -Het bonds.The basic synthetic approaches to these compounds include reactions of metalated thiophenes with phosphorus(III) and (V) halides, phosphorylation of thiophenes in the presence of a mild Lewis acid, use of halogenothiophenes in the Arbuzov reaction, and phosphorylation of thiophenes with phosphorus(III) halides in basic medium. Synthetic approaches to condensed heterocyclic systems of novel types are also considered.Investigation of chemical properties of phosphorylated thiophenes has revealed that, despite the great similarity with phenyl analogues, differences connected to the nature of the heterocycle are observed. The tertiary phosphines bearing at least one thienyl substituent are less active in quaternization and oxidation reactions. At the same time, basic hydrolysis leading to C-P bond cleavage is facilitated, as compared to benzene derivatives.

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Formation of a Bowl‐Shaped, Pentacyclic Phosphonium Cage by Methylation of a Nucleophilic Phosphinidene

et al. 2005

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Dedicated to Professor Gottfried Huttner on the occasion of his 68th birthdayPhosphinidenes, that is, carbene-analogous compounds of monovalent phosphorus (phosphanylidenes, RÀP) represent a simple class of valuable electrophilic building blocks in organophosphorus chemistry, which are usually highly reactive transients and therefore difficult to isolate. [1] However, one simple chemical trick that aids the preparation of a room-temperature stable phosphinidene is the intra-or intermolecular addition of a donor group D to the initially electron-deficient phosphorus atom (D!PR); this affords an electron-rich (nucleophilic) phosphinidene, having eight or more valence electrons at the phosphorus center. Several types of donor-stabilized phosphinidenes have already been isolated and used as versatile precursors for the preparation of "free" phosphinidenes such as phospha-Wittig reagents (R 3 P = PR') [2] and related phosphinidene metal complexes (L n M = PR).[3] The intramolecular donor-stabilization of a P(+1) atom is also the reason for the intriguing stability of the nucleophilic phosphinidene 1 (Scheme 1), which has a planar, T-shaped three-coordinate phosphorus atom with 10 valence electrons (10-P-3 system).[4] Although 1 is a promising versatile building block for the synthesis of novel electronically tunable organophosphorus ligands, its reactivity has only been sparingly investigated.[5] The relatively high nucleophilicity at the P atom prompted us to investigate whether alkylation of phosphorus with classical alkylation reagents RX (R = alkyl; X = anionic leaving group) leads to a nucleophilic phosphenium salt A, phosphonium species B, or neutral phosphorane C as possible valence isomers, depending on the electronic nature and steric demand of R and X, respectively (Scheme 1).Here we report the surprising formation of the unusual phosphonium cage cation in 2, which results from a domino cyclization of two molecules of 1 in the presence of methyl trifluoromethylsulfonate (MeOTf). When a solution of MeOTf in CH 2 Cl 2 was added to a solution of 1 in CH 2 Cl 2 in the molar ratio of 1:1 at 20 8C, a rapid reaction occurs ( 31 P NMR monitoring), affording the unexpected phosphonium salt 2 [Eq. (1)]. The latter is insoluble in hydrocarbon solvents and other nonpolar solvents and can be isolated in the form of a colorless solid in 35 % yield. The yield can be increased up to 78 % by changing the molar ratio of the starting materials MeOTf and 1 to 1:2. Interestingly, compound 2 results also exclusively even if a solution of 1 in CH 2 Cl 2 is slowly added to a very large molar excess or even by using neat MeOTf at room temperature or below (À10 8C). The composition and constitution of 2 was established by EI-FAB and ESI (electrospray ionization) mass spectrometry Scheme 1. The possible valence isomers A, B, and C formed by alkylation of 1 with RX (R = alkyl, X = anionic leaving group; ET = electron transfer.

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Two new syntheses of the “phospha‐wittig” reagents

Abstract: ABSTRACT

Cited by 13 publications

References 13 publications

Revisiting the Phospha-Wittig–Horner Reaction

Revisiting the Phospha-Wittig–Horner Reaction

Phosphorylation of Thiophenes

Formation of a Bowl‐Shaped, Pentacyclic Phosphonium Cage by Methylation of a Nucleophilic Phosphinidene

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