Reductive Polycondensation. Synthesis of Polyethers Consisting of One Unit from Dialdehydes and of Polyethers Consisting of Two Alternating Units from Dialdehydes and Alkylene Bis(trimethylsilyl) Ethers1

Facile synthesis of polyethers of the type (A-O) n is achieved by triphenylmethyl (trityl) perchlorate-catalyzed reductive condensation of dialdehydes with triethylsilane, and the method was also extended to the synthesis of polyethers of the type (A-O-B-O) n by the reductive polycondensation of dialdehydes and alkylene bis(trimethylsilyl) ethers. The reductive polycondensation of isophthalaldehyde (1a) proceeded even at -50 °C to yield the polyether consisting of one unit derived from 1a. Dialdehydes with weak electron-withdrawing groups such as ester, carbonate, and bromide also underwent the reductive polycondensation to yield the corresponding polyethers having such functional groups. Especially, bis(4-formylphenyl) succinate (1b) resulted in the polyether with the highest molecular weight of dialdehydes investigated. The reductive polycondensations of dialdehydes 1 and alkylene bis-(trimethylsilyl) ethers 2 were carried out with dimethylphenylsilane to yield the polyethers consisting of alternating 1 and 2 units. Primary and secondary 2 were effective for obtaining polyethers of the type (A-O-B-O) n by the reductive polycondensation of 1 and 2.