摘要:
Acylation of Ph2P(O)Me with a lactone gives a Horner-Wittig intermediate with a Z-double bond protected as a Diels-Alder adduct with furan and hence (Z)-penta-2,4-dien-1-ol. Substituted (E)-penta-2,4-dien-1-ols are available by a more general route involving addition of enals to phosphine oxides, a regiochemically controlled allylic alcohol transposition, and a Horner-Wittig reaction. The geometry of only one double bond can be controlled.