Geometrically directed lithiation of O‐Alkyloximes for the synthesis of linear polyethers

For synthetic purposes, the polyether‐based secondary alcohols 7 and 8 were prepared from acetone O‐methyloxime (1). This applies the (Z) effect for the geometry‐directed alkylation sequence, recovery of the keto group and reduction. In contrast to 11, α‐phenylthio‐substituted O‐alkyloxime 26 was found to be unsuitable as starting material for such synthesis. The strong effect of bivalent sulfur in the α‐position shadows the (Z) effect and permits only lithiation next to the sulfur atom.