Synthesis of Vinylcyclopropanes, Cyclopropyl Vinyl Ketones, and 3-Pyrazolyl Vinyl Ketones from 1-Diazo-3-trimethylsilylpropanone

Article abstract of DOI:10.1246/bcsj.59.2851

Reaction of 1-diazo-3-trimethylsilylpropanone with olefins in the presence of 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 vinyl ketones in good yields, respectively.Cycloaddition of 1-diazo-3-trimethylsilylpropanone with acetylenes and similar carbon-carbon bond formation at the side chain of the cycloadducts lead to 3-pyrazolyl vinyl ketones.