FORMATION OF UNEXPECTED SILICON ALKOXIDE ISOMERS IN A RECTANGULAR PLANAR CHELATING FRAMEWORK

Reaction of the tetraols {formula-omited} with (MeO)3SiMe in the presence of base is facilitated by the absence of solvent. The polymeric intermediate from the reaction involving 1 partially depolymerizes when heated under vacuum to give a pair of stable tetracyclic isomers 6a,b as sublimates. In 6a the MeSiOSiMe moiety spans the rectangular array of alkoxy oxygens such that the CSiOSiC plane of this group is parallel with the hydrocarbon three-membered ring, while in 6b it is perpendicular to the ring. Depolymerization of the intermediate from the reaction involving 5 gives a tricyclic product in which an MeSi group spans three alkoxy oxygens. The structures of of 6a, 6b, and 7 were determined by X-ray crystallography. © 1990, American Chemical Society. All rights reserved.