Reactivity of phosphonium diylids with esters and amides
The phosphonium diylid (C6H5)2P(CH2)(CH2Li) reacts readily with various esters and amides to give acylated phosphonium salts and Wittig products.In the case of N,N-dimethylbenzamide the reaction can be directed mainly to the Wittig products by protonation.Depending on the nature of the carbonyl group, unexpected reactions, such as conjugate additions to α,β-unsaturated compounds or enolization of α-hydrogenated amides, can also take place.