Asymmetric [2,3]-Wittig Rearrangement Induced by a Chiral Carbanion Whose Chirality Was Transferred from an Epoxide

The enantioselective [2,3]-Wittig rearrangement of 1-allyloxy-1-(naphthalen-2-yl)-4-siloxy-2,4-pentadienyl anion, derived from optically enriched 4,5-epoxy-1-(naphthalen-2-yl)-5-silyl-2-pentenyl allyl ether via a base-induced ring opening of the epoxide followed by Brook rearrangement, has been studied. The chirality of the epoxide was transferred to the alcohols in up to 97% ee, depending on the solvent used. The best result was obtained in 1,4-dioxane at a temperature above room temperature.