2- Methyl-2,3-butadienoate, addition with

In 1985, Cristiau et al. reported that the reaction of methyl 2,3-butadienoate with PPh3 followed by the addition of Nal afforded phosphonium iodide 532, which makes the y-carbon prone to nucleophilic attack, leading to the formation of 4-meth-oxy-2-enonate 533 [197a]. 

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