Establishment of an efficient synthetic route to 3,4:3',4'-Bis(3,6,9-trioxaundecane-1,11-dioxy)benzil

3,4:3',4'-Bis(3,6,9-trioxaundecane-1,11-dioxy)benzil (1) [bis(crown ether)benzil] was prepared by three different routes in which the third route C, including the method of Sonogashira-coupling, was the most efficient method with the overall yield of 50%. Further, the method of synthesizing the novel compound 3,4:3',4'-bis[3,4-(3,6,9-trioxaundecane-1,11-dioxy)]benzoin (6) [bis(crown ether)benzoin], which has not yet been prepared appropriately, was also provided.