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Names | |
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Preferred IUPAC name
Methylidenetri(phenyl)phosphane | |
Identifiers | |
3D model (
JSmol)
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ChemSpider | |
PubChem
CID
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UNII | |
CompTox Dashboard (
EPA)
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Properties | |
C19H17P | |
Appearance | yellow solid |
Density | 1.19 g/cm3 |
decompose | |
Solubility | THF |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Methylenetriphenylphosphorane is an organophosphorus compound with the formula Ph3PCH2. It is the parent member of the phosphorus ylides, popularly known as Wittig reagents. It is a highly polar, highly basic species.
Methylenetriphenylphosphorane is prepared from methyltriphenylphosphonium bromide by its deprotonation using a strong base like butyllithium: [1]
The phosphorane is generally not isolated, instead it is used in situ. The estimated pKa of this carbon acid is near 15. [2] Potassium tert-butoxide has been used in place of butyl lithium. [3] Sodium amide has also been used a base. [4]
Methylenetriphenylphosphorane is used to replace oxygen centres in aldehydes and ketones with a methylene group, i.e., a methylenation:
The phosphorus-containing product is triphenylphosphine oxide.
Crystallographic characterization of the colourless ylide reveals that the phosphorus atom is approximately tetrahedral. The PCH2 centre is planar and the P=CH2 distance is 1.661 Å, which is much shorter than the P-Ph distances (1.823 Å). [5] The compound is usually described as a combination of two resonance structures:
Methylenetriphenylphosphorane has become a standard tool for synthetic organic chemists. [6]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
![]() | |
![]() | |
Names | |
---|---|
Preferred IUPAC name
Methylidenetri(phenyl)phosphane | |
Identifiers | |
3D model (
JSmol)
|
|
ChemSpider | |
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C19H17P | |
Appearance | yellow solid |
Density | 1.19 g/cm3 |
decompose | |
Solubility | THF |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Methylenetriphenylphosphorane is an organophosphorus compound with the formula Ph3PCH2. It is the parent member of the phosphorus ylides, popularly known as Wittig reagents. It is a highly polar, highly basic species.
Methylenetriphenylphosphorane is prepared from methyltriphenylphosphonium bromide by its deprotonation using a strong base like butyllithium: [1]
The phosphorane is generally not isolated, instead it is used in situ. The estimated pKa of this carbon acid is near 15. [2] Potassium tert-butoxide has been used in place of butyl lithium. [3] Sodium amide has also been used a base. [4]
Methylenetriphenylphosphorane is used to replace oxygen centres in aldehydes and ketones with a methylene group, i.e., a methylenation:
The phosphorus-containing product is triphenylphosphine oxide.
Crystallographic characterization of the colourless ylide reveals that the phosphorus atom is approximately tetrahedral. The PCH2 centre is planar and the P=CH2 distance is 1.661 Å, which is much shorter than the P-Ph distances (1.823 Å). [5] The compound is usually described as a combination of two resonance structures:
Methylenetriphenylphosphorane has become a standard tool for synthetic organic chemists. [6]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)