Hydroxyl terminated polyethers find uses as raw materials of polyurethane and polyester resins. Others uses include cosmetics, plasticizers, surfactants and raw materials of these products. Conventional polyethers are terminated with primary or secondary alcoholic groups, the presence of which normally contributes to their desirablity for intended uses. It has been experienced in certain cases that the primary or secondary alcohol function is too active and therefore the presence of which is not desirable. For example, polyethers having too active an alcoholic function can lead to a premature reaction when reacted with polyisocyanates. Attempts have been made to remove the hydroxyl function by blocking with a group such as methyl or acyl, or replacing the hydroxyl group with chlorine. Obviously, polyethers having blocked or chlorinated terminals are not suitable for uses in which the presence of a hydroxyl function is essential, e.g. for the production of polyurethane and polyester resins.