壹、研究1,3-雙羰基化合物與醛醣半縮醛之Knoevenagel縮合反應 貳、研究氮-苯甲基脯胺酸脫羰基反應形成之亞胺離子與1,3-雙羰基化合物之加成反應

Abstract

['透過對D-ribose 2,3,5-位羥基進行保護/修飾後，利用半縮醛醣體1-位碳具有半縮醛官能基，以及環狀1,3-dicarbonyl化合物α-位碳具有較低pKa值之之特性，進行Knoevenagel condensation形成Knoevenagel產物，並作為Michael acceptor，再與核醣4-碳上的二級醇進行進行Michael addition反應形成enolate中間體，並研究其合成應用。\n此外，以cyclic 1,3-dicarbonyl化合物1-benzylproline經脫羰基反應後所形成之1-pyrrolinium進行Mannich反應，合成一系列N-benzylpyrrolidine衍生物。分別以cyclic 1,3-dicarbonyl化合物在不加入鹼試劑的條件下，直接與1-pyrrolinium進行Mannich反應，以及加入鹼試劑與cyclic 1,3-dicarbonyl化合物形成金屬烯醇鹽類，再以金屬烯醇鹽類與1-pyrroliuinm中間體進行Mannich反應，並比較在兩種條件下cyclic 1,3-dicarbonyl化合物的親核性差異。並且透過1H-NMR、13C-NMR、2D-NMR針對N-pyrrolidine衍生物進行結構鑑定，判斷1,3-dicarbonyl的Mannich產物是以C-alkylation之烯醇形式接在N-benzylpyrrolidine之2-位碳上。\n']

['1,3-Dicarbonyl compounds can undergo Knoevenagel condensation with the hemiacetal functionality of D-ribofuranoside derivatives with protection/modification of the hydroxyl groups at the 2,3,5-positions to form the Knoevenagel adduct as the Michael acceptor intermediate. Subsequently, the secondary hydroxyl group at the C-4 position attacks the Michael acceptor to form the enolate intermediate. A brief survey was conducted to study the potential synthetic application of the resulting enolate intermediate.\nFurthermore, cyclic 1,3-dicarbonyl compounds are applied to the Mannich reaction with 1-pyrrolinium from decarbonylation reaction of 1-benzylproline, and synthesis a series of N-benzylpyrrolidine derivatives. We investigated the nucleophilic addition of 1,3-diketone derivatives to the N-benzylpyrrolinium, and compare the reaction outcomes under base condition and neutral condition. We observed all the Mannich adducts from C-alkylation of 1,3-dicarbonyl products. We used 1H-NMR, 13C-NMR and 2D-NMR to elucidate the structure of Mannich adduct and determined the product exists in enol form.\n']