Abstract
A synthesis of [2]rotaxanes in which Zn(II) or Cu(II) Lewis acids catalyze a Diels-Alder cycloaddition to form the axle while simultaneously acting as the template for the assembly of the interlocked molecules is described. Coordination of the Lewis acid to a multidentate endotopic 2,6-di(methyleneoxy-methyl)pyridyl- or bipyridine-containing macrocycle orients a chelated dienophile through the macrocycle cavity. Lewis acid activation of the double bond causes it to react with an incoming "stoppered" diene, affording the [2]rotaxane in up to 91% yield. Unusually for an active-template synthesis, the metal binding site "lives on" in these rotaxanes. This was exploited in the synthesis of a molecular shuttle containing two different ligating sites in which the position of the macrocycle could be switched by complexation with metal ions [Zn(II) and Pd(II)] with different preferred coordination geometries.
Original language | English |
---|---|
Pages (from-to) | 5309-5314 |
Number of pages | 6 |
Journal | Journal of the American Chemical Society |
Volume | 132 |
Issue number | 14 |
DOIs | |
Publication status | Published - 14 Apr 2010 |
Keywords
- DIFFERENT COORDINATING UNITS
- TRANSITION-METAL
- INTERLOCKED MOLECULES
- CHIRAL AMPLIFICATION
- ANION TEMPLATION
- MECHANICAL BONDS
- COPPER COMPLEX
- CATENANES
- RING
- CYCLOADDITIONS