Elimination Reaction of α,β-Dihydroxysilanes:Stereospecific Synthesis of Silyl Enol Ethers from Vinylsilanes

Article abstract of DOI:10.1021/ja00300a031

α,β-Dihydroxysilanes were prepared from vinylsilanes by osmium tetroxide catalyzed hydroxylation, and in a few cases by acid-catalized hydrolysis of the corresponding α,β-epoxysilanes.When α,β-dihydroxysilanes are treated with base, elimination reactions occur via both α- and β-oxidosilanes.With sodium hydride in ether, the α-oxidosilane pathway leading to silyl enol ethers is nearly the exclusive process.This reaction is shown to be highly stereospecific and prefentially anti.The overall process(osmium tetroxide catalyzed hydroxylation followed by treatment with sodium hydride in ether) provides a synthetisally useful method for conversion of vinylsilanes to silyl enol ethers with overall retention of double-bond configuration.