Reduction of Organosilicon Peroxides: Ring Contraction and Cyclodimerization

The
reduction of 1,2,7,8-tetraoxa-3,6-disilonanes is accompanied
by the selective transformation of two SiOOC moieties into SiOC moieties,
resulting in contraction of the nine-membered ring bis-peroxide to
a previously unknown class of seven-membered-ring acetals, 1,6-dioxa-2,5-disilepanes.
The reduction of six-membered cyclic peroxide proceeds differently
and affords four- and eight-membered rings. As a result, silyl ethers
of gem-diols, which do not exist in the free form,
are produced.