Ring contraction of 1,2,4,5,7,8-hexaoxa-3-silonanes by selective reduction of COOSi fragments. Synthesis of new silicon-containing rings, 1,3,5,6-tetraoxa-2-silepanes.

The reducing agents Ph(3)P, (C(8)H(17))(3)P, or NH(2)C(S)NH(2) promote the ring contraction of nine-membered triperoxides, viz., 1,2,4,5,7,8-hexaoxa-3-silonanes, giving rise to seven-membered rings belonging to the previously unknown class of monoperoxides, viz., 1,3,5,6-tetraoxa-2-silepanes, in yields from 67% to 91%. Therefore, the selective reduction of the SiOOC fragments to SiOC in molecules containing simultaneously the COOC fragment was performed for the first time.

Synthesis of 1-hydroperoxy-1'-alkoxyperoxides by the iodine-catalyzed reactions of geminal bishydroperoxides with acetals or enol ethers.

It was found that iodine-catalyzed reactions of geminal bishydroperoxides with acetals proceed with the replacement of only one alkoxy group by the peroxide group to give previously unknown structures of 1-hydroperoxy-1'-alkoxyperoxides in yields up to 64%. The same compounds are formed in the iodine-catalyzed reactions of geminal bishydroperoxides with enol ethers. The nature of the solvent has a decisive influence on the formation of 1-hydroperoxy-1'-alkoxyperoxides. In the series of Et(2)O, THF, EtOH, CHCl(3), CH(3)CN, and hexane, the best results were obtained with the use of Et(2)O or THF as the solvent.

Synthesis of cyclic peroxides containing the Si-gem-bisperoxide fragment. 1,2,4,5,7,8-Hexaoxa-3-silonanes as a new class of peroxides.

A method was developed for the synthesis of the previously unknown class of organic peroxides, 1,2,4,5,7,8-hexaoxa-3-silonanes, based on the reaction of dialkyldichlorosilanes with 1,1'-dihydroperoxyperoxides. 1,2,4,5,7,8-Hexaoxa-3-silonanes are rather stable under ambient conditions and were characterized by NMR spectroscopy, X-ray diffraction, and elemental analysis. Their yields are in a range of 59-96%. The attempts were made to prepare 1,2,4,5-tetraoxa-3-silinanes by the reaction of dialkyldichlorosilanes with gem-bishydroperoxides. 1,2,4,5-Tetraoxa-3-silinanes were detected by NMR spectroscopy; these compounds rapidly decompose upon isolation.

New preparation of 1,2,4,5,7,8-hexaoxonanes.

A new versatile procedure was developed for the synthesis of 1,2,4,5,7,8-hexaoxonanes based on the Lewis acid catalyzed reaction of acetals with 1,1'-dihydroperoxydicycloalkyl peroxides. The procedure substantially extends the structural diversity of these compounds and, in most cases, allows the synthesis of these compounds in higher yields (to 96%) and with higher selectivity. Complexation of hexaoxonane with chloroform was documented for the first time. The structures of several triperoxides were established by X-ray diffraction.