THERMAL REARRANGEMENT OF AROMATIC ACETAL AND THIOACETAL DERIVATIVES

Thermolysis of benzaldehyde dibenzyl acetal 1 by refluxing at :250 deg rees C for 3 days give H2O, toluene, benzaldehyde, benzyl alcohol, bib enzyl, stilbene and benzylphenylcarbinol. Similar treatment of cinnama ldehyde diphenyl thio-acetal 2 furnishes H2S, bibenzyl, toluene, stilb ene, thiophenol, diphenyl sulfide, indene, thianthrene, 2,3,4,5-tetrap henylthiophene and polystyrene. Moreover thermolysis of 1 in the prese nce of isoquinoline gives 1-benzylisoquinoline in addition to the prev ious products. From these results a free radical mechanism has been po stulated to take place through the initial homolysis of different bond s in the acetal molecules.