Reactions of an Isolable Dialkylsilylene with Ketones

The reactions of isolable dialkylsilylene 2,2,5,5-tetrakis(trimethylsilyl)-1-silacyclopentane-1,1-diyl with different types of ketones such as adamantanone, acetone, benzophenone, and cyclopropenones proceed smoothly at room temperature to afford the corresponding siloxirane, silyl enol ether, 2-oxa-silacyclopentene, and unusual cyclopropenylsilanes, respectively, without formation of any secondary or side-reaction products. The electronic structure of various types of model carbonyl silaylides was investigated using DFT calculations. The diversity of the reaction modes is explained by invoking the substituent effects on the electronic nature of the initially formed carbonyl silaylides.