An efficient method to obtain phospharanes from triphenylphosphine (TPP) and maleic anhydride (MA), dialkyl maleates, N-aryl maleimides and methyl N-aryl maleanilates is reported. These stabilised phosphoranes react with aromatic aldehydes to yieldE-olefins but fail to react with monoketones and 1,2-diketones. With the more reactive triketone, ninhydrin, the reaction is positive. The order of reactivity of these reagents in olefination appears to be imides=isomaleimides>maleanilates>dialkyl maleates>anhydrides.
