reactions of enol ethers (ROCC, R = alkyl, silyl) with zinc carbenoid reagents were found to give allylic ethers in several cases along with the expected cyclopropylethers. The ratio of these two products was highly dependent on the concentration of the reaction mixture. Thus, the selective formation of each product was conveniently attained by merely changing the amounts of the solvent used. Zinc iodide
Synthesis of β-mercuri ketones by the reaction of siloxycyclopropanes with mercuric acetate and their conversion to α-methylene ketones and γ-ketoesters
Siloxycyclopropanes were quantitatively converted to β-acetoxymercuri ketones by the reaction with mercuricacetate. Successive treatment with palladium chloride or palladium chloride/carbon monoxide gave α-methylene ketones or γ-ketoesters, respectively, in good yields.
Tertiary cyclopropanol systems react with a catalytic amount of vanadyl acetylacetonate under an oxygen atmosphere to afford β-hydroxyketones and β-diketones.
Facile ring opening of siloxy cyclopropanes by photoinduced electron transfer. A new way to β-keto radicals
作者:Heiko Rinderhagen、Prashant A. Waske、Jochen Mattay
DOI:10.1016/j.tet.2006.03.060
日期:2006.7
Siloxy cyclopropanes undergo ring opening and fragmentation of formal silyl cations under formation of β-keto radicals. These reactive intermediates can be used in inter- and intramolecular addition reactions leading to complex ring systems if more than one unsaturated side chain is present in the starting material. Beside some synthetic examples mainly the mechanism will be discussed focusing on the
Efficient Fragmentation of the Tertiary Cyclopropanol System: Oxidation of 1-(Trimethylsiloxy)bicyclo[n.1.0]alkanes and Analogues By Using Phenyliodine(III) Diacetate