P-41 プラコートンEおよびその関連化合物の合成研究(ポスター発表の部)
スポンサーリンク
概要
- 論文の詳細を見る
Plakortone E (1) was isolated as a metabolite of Caribbean sponge, Plakortis simplex, and it was shown to exhibit cytotoxic activity against a murine fibrosarcoma cell, in vitro. The relative configuration of the core moiety in this compound was determined by spectroscopic analysis, however, the stereochemistry of the side chain and the absolute configuration are still unknown. Methyl ester 6, which is a major metabolite of P. halichondrioides, has the same carbon framework as 1 and its absolute configuration was determined in 1996. Here we present the stereocontrolled synthesis of 6, derivation of the synthetic intermediate to C(8)-epi-plakortone E, and the determination of the relative configuration of 1. The key step of the synthesis is 1,5 C-H insertion reaction of alkylidenecarbene to construct the chiral quaternary center. Ketoaldehyde 9 was treated with methyl diazomethylphosphonate and t-BuOK to give dihydrofurane 8 in 69% yield. Alkylation of terminal alkyne of 8 followed by reduction of the triple bond afforded E-alkene 20, which was converted to methyl ester 21 through 3 steps. Phenylselenylation of 21 and the subsequent oxidative elimination gave 6. The NMR spectra of 6 were identical with those of the natural product. For the synthesis of 2, we introduced the double bond of the side chain at a final stage, since as the double bond prohibited the reaction to construct the core part. Ketone 29 was treated with TMSC(Li)N_2 to give dihydrofurane 30 in 81% yield. Then 30 was converted to carboxylic acid 32 through 4 steps. Iodolactonization of 32 afforded the lactones 33 and 34 in 94% yield as a 1: 1 mixture of separable diastereomers. After reduction of 33, the resultant aldehyde 35 underwent the modified Julia olefination to give 2. The NMR spectra of 2 were identical with those of C(8)-epi-plakortone E. The determination of the absolute configuration is now in progress, and will be reported at the symposium.
- 天然有機化合物討論会の論文
- 2005-09-15
著者
関連論文
- CONFIGULATION AT C-23 IN 5β-CHOLESTANE-3α, 7α, 12α, 23-TETROL EXCRETED BY PATIENTS WITH CEREBROTENDINOUS XANTHOMATOSIS
- 118(P-72) 放線菌F-40株の生産する新規オーキシン信号伝達阻害剤Terfestatin A(ポスター発表の部)
- 天然N-acyl sphingomyelin及びN-(C24:O)-sphingomyelin : 水系における層間水の挙動-D_2O-NMRによる評価
- P-56 オルトキノンの環化付加反応を利用したクレオミスコシンCの合成研究(ポスター発表の部)
- P-41 プラコートンEおよびその関連化合物の合成研究(ポスター発表の部)
- 56(P-31) トレハラーゼ阻害剤(+)-トレハゾリンの立体選択的形式全合成(ポスター発表の部)
- 96(P35) 植物由来のトポイソメラーゼII阻害活性を有するポリフェノール類(ポスター発表の部)
- P-13 ビシクロ[3.1.0]ヘキサン化合物の不斉合成とその求核的開環反応を利用した天然物の合成(ポスター発表の部)
- シクロプロパン環の開裂反応を利用した生理活性天然有機化合物の合成研究
- 44 二重に活性化されたシクロプロパン環の開裂反応の天然物合成への利用(口頭発表の部)
- グリニヤール試薬による三員環の開裂反応の天然物合成への利用(有機化学・天然物化学-反応と合成(糖, アミノ酸, テルペン, その他)-)
- シクロプロパン環の開裂反応を利用した生理活性天然有機化合物の合成研究