In the presence of I₂, the model compound 3,9-diphenyl-2,4,8,10-tetraoxa-spiro[5.5]undecane (1) was prepared by the reaction of benzaldehyde with pentaerythritol. The reaction of 1,3-benzodialdehyde with different equivalent of pentaerythritol afforded 1,3-di(2,6-dioxa-4,4-dihydroxymethyl-cyclohexyl)- benzene (2) and 2,4,8,10-tetraoxa-3,9-di(3'-formylphenyl)spiro[5.5]undecane (3), respectively. The title compound poly-acetal-spiro-vic-diether (4) was synthesized in 95.4% yield by the reaction of 2 with 3. The structures of compounds 1, 3 and 4 were characterized by FTIR and ¹H NMR. In the ¹H NMR spectra, the signals of eight hydrogen atoms of methylene groups in chiral axis-containing compounds 1, 3 and 4 were split into four groups of the doublets, but the corresponding signal of the hydrogen atoms was a single peak in compounds 5 and 6 un-containing chiral axis. This difference was not due to the presence of rigid cycle but the presence of chiral axis.

Key words: 1,3-benzodialdehyde, pentaerythritol, poly- acetal-spiro-vic-diether, 3,9-diphenyl-2,4,8,10-tetraoxa-spiro[5.5]undecane