Stéréochimie de la substitution d'un éther allylique par un organomagnésien en présence de sel cuivreux

The nucleophilic substitution of allyl ethers by an organomagnesium reagent in the presence of a catalytic amount of copper(I) salt occurs by antarafacial attack, either with or without allylic rearrangement. It can be compared to the substitution of allyl esters by lithium organocuprates. The leaving group must be quasi orthogonal to the plane of the double bond. A mechanism is postulated.