Silacyclophanones 3*. Cyclic organosilicon esters of ortho-phthalic acids

Reactions of dichlorodimethylsilane with 2,3,4,5-tetrafluorophthalic acid bis(trimethylsilyl) ether (1:1, 20°C, 24 h) without a solvent and dichloro(chloromethyl)methylsilane and dichloro(methyl)phenylsilane with bis(trimethylsilyl) ester of ortho-phthalic acid (1:1, 20°C, 168–264 h) in hexane lead to the formation of previously unknown 14-membered cyclic organosilicon esters of ortho-phthalic acids (silacyclophanones) in 36–85% yields. Molecular structures of 14-membered cyclic ethers 4,10-dimethyl-4,10-diphenyl-3,5,9,11-tetraoxo-4,10-disyla-1,7(1,2)-dibenzacyclododecaphane-2,6,8,12-tetraone, 4,4,10,10-tetramethyl-3,5,9,11-tetraoxo-4,10-disila-1,7(1,2)-di-(tetrafluorobenza)cyclododecaphane-2,6,8,12-tetraone, along with bis(trimethylsilyl) esters of 2,3,4,5-tetrafluorophthalic and orthophthalic acids, were studied by X-ray structural analysis.