Facile synthesis and bridgehead-functionalization of bicyclo[3.3.3]pentasiloxanes

Abstract

A fascinating but still rare bicyclic siloxane, bicyclo[3.3.3]pentasiloxane, was synthesized by the oxidation of a bicyclic silicon cluster and characterized using a combination of NMR spectroscopy and X-ray diffraction analysis. The bridgehead OSiMe₃ groups of the siloxane were selectively and efficiently converted to O⁻K⁺ (siloxide) by treating with ^tBuOK in the presence of 18-crown-6-ether. The resulting siloxides provided various bridgehead-functionalized bicyclo[3.3.3]pentasiloxanes after treatment with electrophiles.