| Summary: | 碩士 === 靜宜大學 === 應用化學系研究所 === 92 === Methyl 5-deoxy-2,3-O-isopropylidene-β-D-erythro-pent-4-enofuranoside 4 has been readily prepared from D-ribose. Employing cerium ammonium nitrate (CAN) to induce a series of 1,3-dicarbonyl compounds, such as: 2,4- pentanedione, ethyl acetoacetate, 1,3-cyclohexanedione, 5,5-dimethyl-1,3- cyclohexanedione, 1-benzoylacetone, dibenzoylmethane, 1,3-dimethyl barbituric acid and 4-hydroxycoumarin etc..., to generate corresponding the electron-poor radicals, which were proceeding [3+2] cycloaddition with 4 to obtain a series of the corresponding optically active dioxabicyclo[4.4] spiro ketals 5 with high stereoselectivity.
In addition, CAN can also induced sodium azide and sodium iodide to produce azido and iodo radicals, which were proceeding the azdiohydroxylation and iodoalkoxylation with 4 in different solvents (CH3CN and small molecule of alcohols). Lactones 19 and 20 were obtained from 4 and 17 respectively by using CAN-sodium nitrite through the oxidative cleavage process.
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