Unsaturated Organosilicon Heterocycles.

Abstract : The generation of carbon-silicon double bonds as reactive intermediates and their cycloadditions with alpha, beta unsaturated aldehydes has been a primary goal. To accomplish this objective 1,1-dimethyl-2-phenyl-1-silacyclobutane was prepared. Pyrolysis of this compound in the gas phase led to ethylene and a reactive intermediate possessing a carbon-silicon double bond with a phenyl substitutent on the carbon atom. Apparently, the phenyl group stabilizes the carbon-silicon double bond. Thus, 1,1-dimethyl-2-phenyl-1-silacyclobutane decomposes at 450 whereas 1,1-dimethylsilacyclobutane does not decompose until 600 under comparable conditions. (Author)