SYNTHESES, STRUCTURE ANALYSES, AND REACTIONS OF 1,3,5-TRIOXEPANES ANDRELATED-COMPOUNDS

Acid-catalysed condensations of 1,5- or 1,6-dicarbonyl compounds with ethylene glycol give 1,3,5-trioxepane derivatives as a result of neigh bouring participation by the adjacent carbonyl group during the acetal ization process. With trimethylene glycol, the related 1,3,5-trioxocan es have also been obtained. Reaction of the 1,3,5-trioxepanes with (a) Grignard reagents gives dialkyl-substituted cyclic ethers, (b) titani um tetrachloride-allyltributyltin gives diallyl-substituted cyclic eth ers and (c) triethylsilane in the presence of trimethylsilyl triflate provides the corresponding cyclic ethers.