cupric acetylacetonate (Cu(acac)2) affords cyclopropyl trimethylsilylmethyl ketones. One-flask procedure for the formation of these silylated ketones and subsequent treatment with organometallics or with lithium diisopropylamide (LDA) and then carbonyl compounds gives a variety of vinylcyclopropanes or cyclopropyl vinylketones in good yields, respectively. Cycloaddition of 1-diazo-3-trimethylsilylpropanone