They can be formed by reacting oligoethylene glycols with oligoethylene glycol ditosylates or dichlorides in a modification of the Williamson synthesis.  
Hydrophilic TEG yoctowells mimic the interactions of these compounds with oligamines.  These compounds are good candidates for rotaxane wheels because of their relatively easy synthesis and modification.  The Manning reaction is used to generate their aza derivatives as well as nitrogen-substituted versions of these molecules, which are known as cryptands.  A twelve-carbon example of this class of molecules catalyzes the formation of  "purple benzene" by complexing the potassium ion of potassium permanganate.  They can be formed by reacting oligoethylene glycols with oligoethylene glycol ditosylates or dichlorides in a modification of the Williamson synthesis.  For 10 points, name this class of macrocyclic organic compounds whose subunits contain oxygen bonded to two alkyl or aryl groups.
Hydrophilic TEG yoctowells mimic the interactions of these compounds with oligamines.  
crown ethers (prompt on ethers)