The synthesis of 4H-pyran containing hemispherands via pyrylium salts

Two new hemispherands 2a and 2b containing a central 4H-pyran unit were synthesized via appropiately substituted 2,6-phenyl pyrylium salts; largest ΔGo values of complexation of 2a and 2b with different alkali picrates are found for Na+ and K+.