著者

山田 英俊 Yamada Eishun

出版者

神奈川大学大学院経営学研究科

雑誌

神奈川大学大学院経営学研究科研究年報

巻号頁・発行日

no.9, pp.47-62, 2005-03

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論文

著者

池内 和忠 若森 晋之介 廣兼 司 山田 英俊

出版者

公益社団法人 有機合成化学協会

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.76, no.9, pp.904-913, 2018-09-01 (Released:2018-09-07)

参考文献数

83

被引用文献数

2

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This review describes synthetic methods that have brought remarkable increase of synthesizable ellagitannins. Acquisition of capability to enable syntheses of all ellagitannins, which are more than 1,000 characterized natural products and their analogues, would contribute to development of understanding structure-activity relationship. The two major reasons diversifying the structures of ellagitannins are the presence of the hexahydroxydiphenoyl group and the C-O digallates, each of which arises through formation of a C-C or a C-O bond between two galloyl groups. To increase the number of synthesizable ellagitannins, establishment of methods for synthesizing these two components and for assembling the components to construct ellagitannin molecules are essential. Three focuses here are methods for synthesizing (1) the hexahydroxydiphenoyl group, (2) glucose derivatives with hexahydroxydiphenoyl bridges, and (3) the C-O digallates. In addition, several applications of these methods for total syntheses of ellagitannins are exemplified.

著者

西沢 麦夫 山田 英俊

出版者

公益社団法人日本薬学会

雑誌

ファルマシア (ISSN:00148601)

巻号頁・発行日

vol.29, no.8, pp.867-872, 1993-08-01

被引用文献数

1

著者

西沢 麦夫 山田 英俊 林 雄二

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.28, pp.370-376, 1986-09-09

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A sweet principle of Phlomis betonicoides, baiyunoside (1a) reported by Tanaka, is a glycoside of 3-substituted furanoditerpene with labdane skeleton. During the series of our investigation dealing with a biomimetic olefin cyclization using mercury(III) triflate/N,N-dimethylaniline complex (2), we have examined the cyclization of some acyclic furano terpenoid, and observed that the cyclization of ambliofuran (3a) is mainly initiated from an internal double bond (Δ^<10>) to give 4 and 5, whereas the corresponding sulfone 3b affords terminal cyclization products 16, 17, and 18. The latter product 18 is a mixture of three isomeric olefins (Δ^<7,8>:Δ^<8,9>:Δ^<8,17>=9:4:3). Thus, the cyclization control of ambliofuran analog not only the initiation point but also the termination mode is essential in order to promote the selective total synthesis of (±)-baiyunol (1b), an aglycon of a sweet substance 1a. A furano ketone 3d is the best substrate to our purpose which gives Δ^<8,9> bicyclic product 28 in high yield. The resulting organomercuric ketone 28 is efficiently transformed to 1b, and which is identified with (+)-baiyunol derived from natural sweet glycoside. Glycosidation of (±)-baiyunol is currently undertaken.

著者

山田 英俊 西沢 麦夫

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.29, pp.349-355, 1987-07-25

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Sweet taste is one of the fascinating field of organic chemistry on the basis of social requirements to find low calorie and high quality taste. Baiyunoside (1) has been characterized as a sweet taste principle of chinese drug, Bai-Yun-Shen (Phlomis betonicoides), by Tanaka and co-workers along with the minor sweet glycoside named phlomisoside I (2). We have designed a general approach to this class of sweet glycosides in order to develop high quality artificial sweeteners. We have already reported an efficient total synthesis of (±)-baiyunol (4), the aglycon of 1 and 2 by means of selective olefin cyclization using mercury(II) triflate/N,N-dimethylaniline complex. We disclose herein the first total synthesis of baiyunoside (1) from (±)-baiyunol (4) via a novel 2' discriminated glycosidation using 2' free glycosyl halide. This novel glycosidation does not accompanied any oligosaccharide formation and this result suggests that very severe steric bulk exist at the newly formed 2' hydroxyl moiety of 6a. As is the case, 6a was entirely inert against a variety of Koenigs-Knorr type glycosidation in order to introduce the xylose moiety. However, Noyori's glycosidation based on a strong affinity between silicon and fluorine was efficiently applied to our purpose. When trimethylsilyl ether 16 was treated with fluorosugar 15 in toluene in the presence of catalytic amount of trimethylsilyl triflate afforded disaccharide 17 and 18 in 38: 62 ratio and in 58% yield. Deprotection of the latter afforded baiyunoside (1) and identified with natural product in every respects. Therefore, we have established a general way to prepare a wide variety of baiyunoside analogs in order to evaluate the taste.