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The cis,trans trispiro ether 4 is accessible from several synthetic directions as a consequence of a crossover in reaction selectivity when proceeding from nucleophilic attack on the cis dispiro ketone to oxygenation of the alpha,beta-unsaturated ester 17. Its cis,cis isomer 3 was obtained in 17 steps and 14.6% overall yield from 3, 5-dimethoxybenzoic acid by making use of the alicyclic side chain in N as a "conformational lock". Although 4 shows no measurable tendency to complex with alkali metal ions, 3 binds strongly to Li(+) and Na(+) ions, as well as to CH(3)NH(3)(+). Whereas the 3eq conformation is populated in the solid state and in solution, complex formation occurs readily. (13)C NMR studies have defined slow exchange limits as the 2:1 sandwich complex with lithium ion is initially formed and transformed progressively into a 1:1 species upon the addition of more LiClO(4). Only the 2:1 complex with sodium ion is formed during comparable titration with NaClO(4). Association constants, molecular mechanics calculations, and X-ray crystallographic studies provide insight into the binding capacity of this belted tridentate ionophore.

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Vicinal Tetrahydrofuran Polysubstitution of Simulated Fatty Acids.-With a view to synthesizing new ionophoric materials for use as antibiotics, 2 groups of diastereomeric tetrahydrofuryl-substituted long-chain carboxylic acids such as (VII)-(X) are prepared with total stereochemical control. The diastereomeric ionophores are evaluated for their capability of binding of alkali metal ions. -(STEPANIAN, M.; TREGO, W. E.; BOLIN, D. G.; PAQUETTE, L. A.; SARETH, S.; RIDDELL, F. G.; Tetrahedron 53 (1997) 22, 7403-7416; Dep. Chem., Ohio State Univ., Columbus, OH 43210, USA; EN)