Solid-phase synthesis of uniform linear oligoethers with repeating functional arms as multivalent spacers

Polystyrene-bound uniform linear oligoethers, where each repeating unit bears a functional arm, were prepared by stepwise solid-phase synthesis. These oligomeric spacers are an alternative to dendritic oligoethers and preserve the multivalent nature of the latter. L-Proline, immobilized on the support equipped with such oligomeric spacers, induced in the model aldol reaction activity and selectivity, comparable to those of the proline immobilized on a related dendronized support. The functional side chains of the oligoethers can be dendronized, thus increasing, even more, the local density of the functional groups near each attachment site on the polystyrene matrix.