Abstract
A remarkable feature of diethyl-1,3-butadiene-phosphonate, unlike the dienephosphonium salts,2,3 is that it undergoes a simple Michael addition with enolates of aldehydes and ketones without the loss of the phosphorus group.4 Whether such a difference in reactivity exists between the two-carbon reagents, vinyltriphenylphosphonium bromide 1 5 and diethyl vinylphosphonate 2 6 is the subject of this investigation.