Methyltriphenylphosphonium Methylcarbonate, an All-In-One Wittig Vinylation Reagent

The methyltriphenylphosphonium methylcarbonate salt [Ph3 PCH3 ][CH3 OCO2 ], obtained directly by quaternarization of triphenylphosphine with dimethylcarbonate, is a latent ylide that promotes Wittig vinylation of aldehydes and ketones. Alkenes are obtained simply by mixing [Ph3 PCH3 ][CH3 OCO2 ] and the carbonyl and heating in a solvent (no base, no halides, and no inorganic byproducts). Deuterium exchange experiments and the particularly short anion-cation distance measured by XRD in [Ph3 PCH3 ][CH3 OCO2 ] allowed to explain the nature and reactivity of this species. Green chemistry metrics (atom economy, mass index, environmental factor) indicate that this vinylation procedure is more efficient than comparable ones. Deuterated [Ph3 PCD3 ][CH3 OCO2 ] promoted the synthesis of deuterated olefins.