A series of molecular building blocks containing allylsilyl groups, which can be incorporated into the appropriate sol–gel precursors as fragments, were prepared. The allylsilyl group is retained unchanged over the course of all reactions giving sol–gel precursors and behave as the synthetic equivalent of alkoxysilyl groups toward sol–gel polymerization, but are stable enough to allow purification by silica gel chromatography. These allylsilanes were ...