Edge-directed dynamic covalent synthesis of a chiral nanocube

The dynamic multicomponent syntheses of nanometer-sized chiral molecular cubes 1a and 1b from 8 tritopic 90 degrees corner units and 12 linear spacers using an edge-directed approach is described. Thus, the TFA-catalyzed reaction of 8 equiv C3- trihexadecycloxy-triformylcyclotribenzylene 2 as corner unit with 12 equiv of 1,4-phenylenediamine 3a or benzidine 3b as spacers yields nanocubes 1a and 1b, respectively in close to quantitative yield. The same reactions carried out with enantiomerically pure (P)-2(> 99% ee) gave the homochiral cubes (all-P)-1a and (all-P)-1b. Force field calculations predict an edge length of 17 angstrom and 21 angstrom for 1a and 1b, which is consistent with their dimensions estimated from DOSY experiments. Furthermore, the asymmetric syntheses of (P)-2 through dynamic thermodynamic resolution is described. This approach is based on the TFA-catalyzed reaction of racemic 2 with (R,R)-1,2-diaminocyclohexane (R)-5, which leads to a chiral cryptophane (> 90% yield) that is built-up from two (P)-2 linked together with three diamines (R)-5. Hydrolysis of this cryptophane provides (P)-2 with > 99% ee.