Synthesis and transport studies of a new class of cage-annulated chiral macrocycles

The synthesis of a new class of chiral pentacycloundecane cage annulated macrocycles is reported. The ability of the chiral hosts to transport racemic phenylglycine methyl ester enantioselectively through a chloroform membrane in a U-tube was compared to that of related pyridine macrocycles. The cage annulated macrocycles showed weak to moderate enantioselectivity and very high rates of transport compared to previous systems reported using the same counter ion (PF6-). The rate of transport was slowed by changing to a relatively harder counter ion (Cl-). (C) 2003 Elsevier Science Ltd. All rights reserved.