The use of polymer supports in organic synthesis. VII. Polymer-bound 1,3-diols as monoblocking agents of symmetrical dialdehydes

Two different 2% cross-linked divinylbenzene–styrene copolymers incorporating 1,3-diol groups were prepared. The symmetrical dialdehydes terephthalaldehyde and o-phthalaldehyde were attached to these polymers through acetal formation, showing that even hindered o-aromatic dialdehydes can be monoblocked by the use of polymer supports. The free aldehyde group of polymer-bound terephthalaldehyde reacted with Wittig reagents to give 1-p-formylphenyl-4-phenyl-1,3-butadiene and p-formylstilbene. Similarly, polymer-bound o-phthalaldehyde gave o-formylstilbenes. Polymer-bound 1,3- and 1,2-diols did not form acetals of aliphatic dialdehydes and formed ketals of symmetrical diketones in very low yield.