Methoxymethylenetriphenylphosphorane
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Names | |
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IUPAC name
Methoxymethylidene(triphenyl)-λ5-phosphane
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Identifiers | |
3D model (JSmol)
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
C20H19OP | |
Molar mass | 306.345 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Methoxymethylenetriphenylphosphorane is a Wittig reagent used for the homologization of aldehydes, and ketones to extended aldehydes, a organic reaction first reported in 1958.[1] The reagent is generally prepared and used in situ. It has blood-red color, indicative of destabilized ylides.
Preparation
[edit]The reagent can be prepared in two steps from triphenylphosphine. The first step is P-alkylation with chloromethyl methyl ether.
- PPh3 + CH3OCH2Cl → [CH3OCH2PPh3]Cl
In the second step, the resulting phosphonium salt is deprotonated.
- [CH3OCH2PPh3]Cl + LiNR2 → CH3OCH=PPh3 + LiCl + HNR2
In place of chloromethyl methyl ether, a mixture of methylal and acetyl chloride can be used.
Uses
[edit]This reagent reacts with a ketone or aldehyde in a Wittig reaction to give an enol ether, which can be converted to the aldehyde by acid-induced hydrolysis.
The initial report of the reaction demonstrated its use on the steroid tigogenone.[2]
It was later used in the Wender Taxol total synthesis and the Stork quinine total synthesis.
References
[edit]- ^ A new aldehyde synthesis Samuel G. Levine J. Am. Chem. Soc.; 1958; 80(22); 6150–6151. doi:10.1021/ja01555a068