Carbomethoxymethylenetriphenylphosphorane

Carbomethoxymethylenetriphenylphosphorane is a chemical compound used in organic syntheses. It contains a phosphorus atom bound to three phenyl groups, and doubly bound to the alpha position of methyl acetate. It undergoes a Wittig reaction. It is used in the Vitamin B12 total synthesis.

Carbomethoxymethylene­triphenylphosphorane

Names
Preferred IUPAC name Methyl (triphenyl-λ5-phosphanylidene)acetate
Identifiers
CAS Number	2605-67-6
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL1715161
EC Number	220-018-4
PubChem CID	17453
UNII	D9MZ753Q8K Y
InChI InChI=1S/C21H19O2P/c1-23-21(22)17-24(18-11-5-2-6-12-18,19-13-7-3-8-14-19)20-15-9-4-10-16-20/h2-17H,1H3 Key: NTNUDYROPUKXNA-UHFFFAOYSA-N
SMILES COC(=O)C=P(C1=CC=CC=C1)(C2=CC=CC=C2)C3=CC=CC=C3
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P302+P352, P304+P340, P305+P351+P338, P321, P330, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Production

Carbomethoxymethylenetriphenylphosphorane can be made via a multistep reaction using bromoacetic acid, dicyclohexylcarbodiimide, and triphenylphosphine. This makes a phosphonium salt, which is converted to the final product by sodium carbonate in water.

Reactions

Carbomethoxymethylenetriphenylphosphorane reacts with aldehydes to give a two carbon atom extension. The carbomethoxymethylene group replaces the oxygen of the aldehyde to give a trans- double bond.