Preparation of alkyl 3-methylalka-2,4-dienoates from γ,δ-unsaturated β-keto esters via the corresponding conjugated unsaturated 3-enol phosphates

Article abstract of DOI:10.1016/S0040-4020(98)00071-4

Methylation of α,β,γ,δ-unsaturated-β-substituted enol phosphates with lithium dimethyl cuprate gave a mixture of (2E,4E)- and (2Z,4E) alkyl 3- methylalka-2,4-dienoates and unsubstituted alkyl alka-2,4-dienoates. An improved synthesis is described for ethyl β-safranate and the insect growth regulator hydroprene.