Search

(+)-trans-Whisky lactone (5) and (-)-cis-whisky lactone (8), (+)-cognac lactone (9) and (+)-eldanolide (10) were synthesized starting from levoglucosenone (1) in optically pure states

Furanoid glycal was utilized as a starting material for the nucleoside derivatives with the aid of benzenesulfenyl chloride. Condensation reaction with silylated nucleic bases was high in the presence of SnCl 4 . Electrophilic addition of benzenesulfenyl chloride to the glycal with substituent also proceeded in high stereoselectivity. Phenylthio-substituted nucleoside was used to convert 2',3'-dideoxynucleoside and 2',3'-didehydro-2',3'-dideoxynucleoside

Levoglucosenone (1,6-anhydro-3,4-dideoxy-β-D-glycero-hex-3-enopyranos-2-ulose, 1) was converted to give 1,6:3,4-dianhydro-β-D-talopyranose (8) in good yield through stereoselective trans-iodoacetoxylation followed by basic hydrolysis

Stereoselectivities in coupling reactions between silylated pyrimidine bases and 3- or 2-α-phenylthio-2,3-dideoxyribose were examined. In the former case, no stereoselectivities were observed when the coupling reactions were performed either with 1-chlorosugar in an S N 2 mode or in the presence of Lewis acids as catalyst in an S N 1 mode. Coupling reaction with 2-α-phenylthio-2,3-dideoxyribose in the presence of Lewis acids, especially SnCl 4 , proceeded with good stereoselectivity to give anomeric mixtures of α:β=1:9. All these nucleosides were converted to 2',3'-didehydro-2',3'-dideoxynucleosides by oxidation to sulfoxides followed by thermal elimination of sulfenic acid

Conformatial analyses of stegobinone,the sex pheromone of the drugstore beetle,and l'-epi-stegobinone were performed by the combination of detail NOE measurements and molecular mechanics calculations.

The coupling reaction between 1-α-chloro-2-deoxyribose derivative and silylated 5-trifluoromethyluracil was examined. The best stereoselectivity was obtained when the reaction was carried out using a large amount of silylated base in the presence of anhydrous zinc chloride

Coupling reactions between 1-chloro-2,3-dideoxyribose and silylated pyrimidines have been examined from the point of stereoselectivity. When the reaction was carried out in chloroform, the selectivity was in the anomeric ratio of α:β=4:6. On the other hand, the presence of tertiary amine raises the selectivity to α:β=3:7

A new and useful synthesis of (+)-trans-whisky lactone (3), (+)-trans-cognac lactone (4) and (+)-eldanolide (5) starting from levoglucosenone (1) is described