Synthesis of siloxanes: XX. Stereochemical investigations of substitution reactions at cyclotrisiloxanes with new types of model compounds

Functional cyclotrisiloxanes [(RMeSiO)(R′ 2SiO)(ClMeSiO)] (R = OSiMe 3, OSi (OSiMe 3) 3; R′= OSiMe 3) and [(PhMeSiO) 2-(XMeSiO)] (X = H, Cl), each as a mixture of two configurational isomers, have been prepared and shown to be useful as model compounds for studying the stereochemical course of substitution reactions at siloxane silicon atoms by 29Si or 1H NMR spectroscopy. As an example, the acetolysis of the chlorocyclotrisiloxanes was studied and found to proceed with retention of configuration.