Base-catalyzed cleavage and homologation of polyhedral oligosilsesquioxanes

Abstract

Readily available Cy₆Si₆O₉ 2 (Cy = c-C₆H₁₁) reacts with aqueous NEt₄OH in THF to afford endo-C_2h-Cy₆Si₆O₇(OH)₄ 3a, which upon further hydrolysis produces CySi(OH)₃ fragments capable of reacting with 3a to produce endo-C₃-Cy₇Si₇O₉(OH)₃ 1b; the reaction of 2 with aqueous NEt₄OH in the presence of (vinyl)Si(OMe)₃ affords endo-C_s-Cy₆(vinyl)Si₇O₉(OH)₃ 1c via trapping of 3a with monosilanes derived from (vinyl)Si(OMe)₃.