Methoxymethylenetriphenylphosphorane is a Wittig reagent used for the homologation of aldehydes, and ketones to extended aldehydes. The reagent is generally prepared and used in situ. It has blood-red color, indicative of destabilized ylides.
The reagent can be prepared in two steps from triphenylphosphine. The first step is P-alkylation with chloromethyl methyl ether.
In the second step, the resulting phosphonium salt is deprotonated.
In place of chloromethyl methyl ether, a mixture of methylal and acetyl chloride can be used.
The use of this chemical as a Wittig reagnt to homologate alehydes and ketones was first reported by Samuel Levine and this process is now sometimes called the WittigâÂÂLevine reaction or the WittigâÂÂLevine homologation The initial product of the Wittig reaction is an enol ether, which can be converted to the aldehyde by acid-catalyzed hydrolysis.
The initial report of the reaction demonstrated its use on the steroid tigogenone.
It was later used in the Wender Taxol total synthesis and the Stork quinine total synthesis.