Thirty-three cyclic polyethers, derived from aromatic vicinal diols and containing from 9 to 60 atoms including 3 to 20 oxygen atoms in the ring, have been synthesized. Some of these have been prepared in good yields without the use of a high-dilution technique. Fifteen of the compounds have been catalytically hydrogenated to the corresponding saturated cyclic polyethers. Many of those containing five to ten oxygen atoms form stable complexes with some or all of the cations of: Li, Na, NH4, RNH3, K, Rb, Cs, Ag(I), Au(I), Ca, Sr, Ba, Cd, Hg(I), Hg(II), La(III), Tl(I), Ce(III), and Pb(I1). Many of these complexes can be isolated in the crystalline form depending on the anion. They appear to be salt-polyether complexes formed by ion-dipole interaction between the cation and the negatively charged oxygen atoms of the polyether ring. The stoichiometry of the complexes is one molecule of polyether per single ion regardless of the valence. Some of the polyethers, by complexing, solubilize inorganic compounds, such as potassium hydroxide and permanganate, in aromatic hydrocarbons. n a preparation of bis[2-(o-hydroxyphenoxy)ethyl]Pedersen 1 Cyclic Polyethers and Their Complexes with Metal Salts a This compound was previously prepared by Luttringhaus and Sichert-Modrow.6 This compound is not derived from an aromatic vicinal diol, but it is included as an example of an unsubstituted crown compound.

7)This argument receives support from the recent isolation of CSHSF~(CO)ZSOZCHZCH=C(CH~)~ L;ia the reaction of Na[CsHsFe(CO)zI and sulfur dioxide with l-chloro-3-methyl-2-butene. The proton magnetic resonance spectrum of the sulfinate exhibits doublets at T 8.08 (CHa) and 6.17 (CHi) with the relative intensity ratio of 6:2, a sharp singlet at T 4.68 (CjHs), and a complex signal at T 4.30-4.95 (CH=C), in complete accord with the proposed allylic attachment.* (8) R. L. Downs and A. Wojcicki, to be published.(9) Although we cannot rule out the possibility that the "rearranged" allyl-S-sulfinato complexes result from the initial formation of the corresponding "normal" allyl sulfinates, which then rapidly undergo isomerization, there is evidence against such a sequence of events. The derivative C~HSF~(CO)ZSOZCHICH=C(CH~)~ retains its identity after 4 hr of refluxing in liquid SO,; a 3 : 1 mixture of the geometric isomers CSHSF~(CO)ZSOZCHZCH=C(CHS)Z and CSH~F~(CO)ZSOZC(CH~)ZCH= CH2 becomes ca. 8 : 1 and 14 : 1 upon refluxing for 4 and 8 hr, respectively, in liquid sulfur dioxide. Thus, at least in this case, isomerization of the sulfinates does occur, albeit of the sterically more hindered CjHsFe-(CO)ZSOZC(CH~)ZCH=CHZ to the less crowded C~HKF~(CO)ZSOZCHZ-CH=C(CHs)z.

The founders of “supramolecular chemistry” include Charles J. Pedersen, Donald J. Cram, and Jean‐Marie Lehn, who shared the Nobel Prize for Chemistry in 1987 for their fundamental research in this area of organic chemistry. Their work focused the attention of many chemists on the cavities formed by certain types of molecules. Cations, anions, or neutral molecules can enter the cavities of specifically designed compounds and are held there by inter‐molecular forces. It is fully justified, therefore, to compare such compounds to biomolecules. How the development began, how it achieved its first successes, and what fascinating possibilities lie in store for future research are discussed by Pedersen and Cram in this issue and by Lehn in the January issue (page 89 ff.). The most recent results from Lehn's research are also reported, appropriately, in this issue.

The most important, and almost unique, property of the macrocyclic polyethers ("crown compounds") is their tendency to form complexes with alkali metal salts and salts with similar cations. Such complexes are held together by electrostatic attraction between the cation and the negatice end of the C -0 dipoles. The stability of the polyether complexes depends primarily upon how well the cation fits into the polyether ring; other factors are the charge density ofthe cation andin solution-the solvating power of the medium. Cyclic polyethers have been successfully employed, inter alia, in experiments with ionic compounds in organic solvents and in studies of ion transport in biological systems.