Diastereoselective formation of methylene-bridged glycoluril dimers

The acid-catalyzed formation of methylene-bridged glycoluril dimers yields the C-2v-diastereomer selectively. Product resubmission experiments establish that the selectivity is the result of thermodynamic control. A modified synthetic route is presented that allows for the preparation of unsymmetrically substituted dimers, We present the X-ray crystal structures of both diastereomers, This class of compounds is useful for studies of self-assembly in aqueous solution.