73(P-61) ビスオキサゾリジンに対するGrignard試薬の立体選択的付加反応を用いた(-)-Dihydrocuscohygrineの不斉合成(ポスター発表の部)
書誌事項
- タイトル別名
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- 73(P-61) Asymmetrical Synthesis of (-)-Dihydrocuscohygrine Using Diastereoselective Addition of Bisoxazolidine with Grignard Reagent
抄録
Dihydrocuscohygrine, C_2-asymmetrical pyrroridine alkaloid, was isolated from Erythroxylon Coca leaves by Turner in 1981. We show here synthetic studies on dihydrocuscohygrine using 6 as a starting material. Our labolatory have been developed that C_2-asymmetrical bisxazolidine obtained easily from 6 and dialdehyde was reacted with Grignard reagent to afford diamine with high diastereoselectivity. First, we tried the synthesis of (-)-deoxycuscohygrine which bisxazolidine(7) could be prepared more simply. A key reaction, addition reaction to bisxazolidine with 1,3-dioxanylethylmagnesium bromide as Grignard reagent proceeded to afford 13 preferentially. Acidic cyclization of 13 provided the desired product(14), which was transformed to 1 via hydrolysis with Raney Ni in methanol. Asymmetrical synthesis of (-)-deoxycuscohygrine was accomplished from bisoxazolidine(7) in 4 steps. Similarly, asymmetrical synthesis of (-)-dihydrocuscohygrine carried out using addition reaction of Grignard reagent to bisoxazolidine(19) prepared from 15 gave diamine(20) with high diastereoselectivity. The absolute configuration at stereogenic center was established as R,R by X-ray analysis of a single crystal of 21. C_2-Asymmetrical synthesis of (-)-dihydrocuscohygrine was also accomplished from 15 in 10 steps and 9% overall yield.
収録刊行物
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- 天然有機化合物討論会講演要旨集
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天然有機化合物討論会講演要旨集 45 (0), 431-436, 2003
天然有機化合物討論会実行委員会
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詳細情報
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- CRID
- 1390001206079985792
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- NII論文ID
- 110006682332
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- ISSN
- 24331856
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可