Convenient Synthesis of New Si-H and Si-Vinyl Functionalized Stereospecific 8-, 12- and 24-Membered Cyclosiloxanes

Abstract

Two approaches to the selective synthesis of polyfunctional stereoregular cyclosiloxanes from polyhedral organometallasiloxanes are reported.The molecules of organometallasiloxanes possess sandwich or globular structure and contain one or two stereoregular organocyclosiloxanolate fragments coordinated to metal ions.According to the first approach organometallasiloxanes were prepared primarily and then were treated with chlorodimethylsilane or dimethylchlorovinylsilane. The second method is based on the initial transforming of organometallasiloxanes into cyclic polysiloxanols reacted afterwards with corresponding chlorosilanes.The synthesized functional stereoregular cyclosiloxanes are fully characterized by NMR-and IR-spectroscopy, HRMS, TGA, and DSC.