Synthesis of novel polyethers in a geometrically precise conformation

[GRAPHICS] A convergent design for the preparation of a polyoxyethylene-based channel molecule is presented, and the synthesis of the key unit 2 required for the projected construction is described. The essential elements of the design included face to face oriented macrorings spaced by rigid trans-fused oxane s, The strategy combines conformational predictability of C-linked oxanyl s ystems and ring-closing metathesis for the synthesis of crown ethers with e ngineerable ion binding abilities.