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Diels-Alder Reactions of tert-Butylphosphaethyne with 1,3,2-Diaza- and 1,2-Azaphosphinines (1998)

Avarvari, Narcis ; Ricard, Louis ; Mathey, François ; [weitere]

Weinheim : Wiley-Blackwell

Liebigs Annalen 1998 (1998), S. 2039-2045

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ISSN: 1434-193X

Schlagwort(e): Phosphorus heterocycles ; Nitrogen heterocycles ; Phosphinines ; Phosphaalkynes ; [4 + 2] Cycloadditions ; Chemistry ; General Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: tert-Butylphosphaethyne (2) undergoes a Diels-Alder reaction with the 1,3,2-diazaphosphinine 1 at room temperature to furnish the diazadiphosphabarrelene 3. In the presence of an excess of 2 in toluene under reflux compound 3 experiences elimination of a molecule of pivalonitrile to afford the 1-aza-2,4-diphosphinine 5 which, in turn, reacts with a further equivalent of 2 to form the transient azatriphosphabarrelene 6. Formation of the final product, the stable tetraphosphatetracyclic compound 4, is the result of a homo Diels-Alder reaction between 6 and yet another equivalent of 2. The structure of 4 has been confirmed by an X-ray crystallographic analysis of its pentacarbonyltungsten complex 7. As a consequence of the high steric overcrowding in 4, complexation occurs exclusively at its phosphaalkene phosphorus atom. The reactivity of 2 towards the four functionally substituted 1,2-azaphosphinines 8a-d has also been examined. At room temperature smooth [4 + 2] cycloaddition reactions proceed to yield the azadiphosphabarrelenes 9a-d. While thermolyses of the barrelenes 9a-c in toluene under reflux lead exclusively to the starting compounds 8a-c by a [4 + 2] cycloreversion process with concomitant elimination of 2, pyrolysis of 9d under the same conditions furnishes the 1,3-diphosphinine 10, also unambiguously identified by analysis of its tpentacarbonyltungsten complex 11.

Materialart: Digitale Medien

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Digitale Medien

γ-Functionalisation of the 1-Phosphanorbornadiene Structure (1999)

Robin, Frédéric ; Mercier, François ; Ricard, Louis ; [weitere]

Weinheim : Wiley-Blackwell

Liebigs Annalen 1999 (1999), S. 1091-1097

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ISSN: 1434-193X

Schlagwort(e): Phosphanorbornadiene ; Allylic metalation ; Allylic bromination ; BIPNOR dioxide ; Chemistry ; General Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: -3-Methyl-substituted 1-phosphanorbornadiene oxides or sulfides such as 1a,b are either metalated by a strong base (n-BuLi or LDA) or brominated by NBS at the methyl substituent. The reaction of the resulting delocalised carbanions 2a,b takes place either at C-2 (H+, MeI) or at the methylene group (Me3SiCl, ClPPh2, I2). In the last case, γ-functional (5a,b or 6a,b) or bridged (7) phosphanorbornadienes are obtained. Similarly, the reaction of 3-bromomethyl-1-phosphanorbornadiene oxides such as 8 with nucleophiles [NaCH(CO2Me)2, PhO-, Me2NH, PhCH2NH2] yields the corresponding γ-functional phosphanorbornadienes 9-12. This chemistry has also been applied to the BIPNOR dioxide 13.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

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Digitale Medien

Synthesis, X-ray Crystal Structures and Reactivity Towards Alkynes of Gold(I)-Phosphinine Complexes (1999)

Mézailles, Nicolas ; Ricard, Louis ; Mathey, François ; [weitere]

Weinheim : Wiley-Blackwell

Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2233-2241

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ISSN: 1434-1948

Schlagwort(e): Phosphorus ; Heterocycles ; Phosphinines ; Gold ; Cycloadditions ; Chemistry ; General Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: The coordination behaviour of 2,6-disilyl-substituted phosphinines towards gold(I) has been examined. The reaction of the bis(trimethylsilyl)phosphinine 1 with [AuCl(SMe2)] gives the corresponding AuCl derivative 2. X-ray crystal structure analysis reveals that the aromaticity of the phosphinine ring is slightly reduced as a result of the poor π-back bonding ability of the AuCl fragment. The same phenomenon is observed in the cationic complex [Au(1)2][GaCl4] (3) which was readily prepared by reaction of two equivalents of 1 with [AuCl(SMe2)] followed by treatment with GaCl3 at low temperature. Reaction of 2,6-bis(phenylethynyldimethylsilyl)phosphinine (4) with the same precursor leads similarly to the complex [AuCl(4)] (5). Interestingly, this complex dimerizes upon crystallization to give the bis(phosphabarrelene) complex 6, also structurally characterized. The formation of 6 results from a [4 + 2] cycloaddition between one alkynyl group of each phosphinine with the other phosphinine subunit. The formation of the cationic complex [Au(4)][GaCl4] (8) occurs under classical conditions but it disproportionates to give the cationic complex [Au(4)2][GaCl4] (9) and colloidal gold deposition. The formation of 9 has been ascertained by treating 8 with one equivalent of ligand 4. Additionally, 9 can also be obtained in a straightforward fashion by treating two equivalents of 4 with [AuCl(SMe2)] followed by treatment with GaCl3 at low temperature. The structure of 9 has been elucidated. Despite a particular arrangement of the alkyne groups which encapsulate the gold coordination sphere, no gold-alkyne interactions are visible.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

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