Kryptanden mit Galactose‐Bausteinen

Cryptands with Structural Units of Galactose Tetrahydroxybis(galactopyrano)‐[18]crown‐6 2 does not reveal under basic conditions in the presence of oligoethylene glycol ditosylates any trans‐annular etherification involving positions 6/6′ or 4/4′, respectively, instead the systems 4a and b with three macrocycles are generated. After protection of the 6/6′‐hydroxy groups a trans‐annular reaction is possible. Thus, the chiral cryptands 6a and b are accessible. Complexing properties in the presence of ammonium ions have been studied for 6a.