Cyclic Tetrasiloxanetetraols: Formation, Isolation, and Characterization

Abstract

Hydrolysis of trialkoxysilanes having various substituents gave cyclic tetrasiloxanetetraols with all-cis isomer as the major fraction in the presence of equimolar amounts of water and sodium hydroxide. All stereoisomers of phenyl derivative were produced by isomerization of the all-cis isomer in the presence of hydrochloric acid, and isolated and identified.

Alkali-Metal-Directed Hydrolytic Condensation of 3-Mercaptopropyltrimethoxysilane

“…The first synthetic method was based on the procedure described by Ito et al [33], originally for the preparation of cyclosiloxanolates with phenyl groups at the silicon atom. The reaction was carried out in ethanol using 3-mercaptopropyltrimethoxysilane as the siloxane precursor and sodium or potassium hydroxide as an alkali metal source.…”

“…The syntheses of cyclotetrasiloxanolates functionalized at the Si atom with simple alkyl [34][35][36][37] and aryl [30,33,34] [33,34], iBu [33,34,36], Me [37], Vi [37], Et [37], iPr [37] tions. The presence of thiol groups in side chains would enable their functionalization by thiol-ene and thiol-yne addition, and thereby preparation of LPSQs with a large variety of functional groups.…”

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

“…[23][24][25] Later this method was used by other research groups too. [26][27][28] In this paper we have generalized data on such objects and describe the synthesis of new stereoregular 8-, 12-and 24-membered functional organocyclosiloxanes with Si-H and Si-Vin functional groups. The presence of functional groups allows utilizing these cycles in various reactions such as hydrosilylation, hydrothiolation, metathesis, Heck reactions and others.…”

Synthesis of macrocyclic tris-cis-tris-trans- dodeca[(phenyl)(hydroxy)]cyclododecasiloxane in carbonic acid solution

“…As for the macrocyclic siloxanols they could not be synthesized by traditional reaction routes used in siloxane chemistry. Successful efforts in synthesis of stereoregular organosiloxanols by means of different synthetic approaches (6)(7)(8)(9)(10)(11) have attracted much attention because of high potential usage of these unique synthons in synthesis of well-defined siloxane structures.…”