51(P11) メソ酒石酸より誘導されるイミンへの求核付加反応を活用する生理活性化合物の合成(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

• The diastereofacial discrimination in the addition of organometallics to carbonyl and imino compounds constitutes one of the most reliable tools for the stereoselective construction of the multiple asymmetric carbons. In the present study we examined the addition of nucleophiles to chiral aldehyde 3 or imine 4, leading to short step syntheses of tetrahydroxy-LCB and a C33-C37 segment of clyculin A. The anti -selective addition of acetylide7 to the chiral aldehyde 3 derived from meso-tartaric acid was conducted with the triisopropoxytitanium derivative to give the desired anti-adduct 8 as a single diastereomer. Subsequent functional group manipulation gave the imine 9, and the addition of a variety of nucleophiles to this particular imine was next investigated. Lithium dithianide in THF added to the imine 4 to give syn-adduct as the sole product, whereas reversal of the diastereoselectivity was observed in the same reaction conducted in the presence of an excess BF_3・Et_2O, giving anti-adduct. In the presence of BF_3・Et_2O, addition of benzyloxymethyl lithium to the imine also gave anti-adduct as the sole product in good yield. Deprotection and the subsequent hydrolysis followed by acetylation gave the pentaacetyl derivative 12 of tetrahydroxy-LCB 1. The same strategy was used for the preparation of the C_<33>-C_<37> segment of Calyculin A 2 in a stereospecific manner. The methods studied for diastereo-control in the reactions of chiral imine or aldehyde with nucleophiles realize the power of the coordination abilities of metal species to heteroatoms in the substrate to build up a suitable environment for the induction of both chiralities. This kind of strategy for the stereodivergent preparation of possible isomers staring from a single chiral source is a result of the abilities of both inorganic and organic reagents to react cooperatively for stereoselectivity control on the addition of nucleophiles.

• 天然有機化合物討論会の論文
• 1999-09-01

著者

• 河本 学

  三重大工

• 清水 真

  Department Of Chemistry For Materials Faculty Of Engineering Mie University

• 清水 真

  三重大工

• 丹羽 靖哉

  三重大工

関連論文

• 30 有機金属分子固有の配位機能を利用した(+)-デオキシビオチンの立体選択的合成(口頭発表の部)
• 51(P11) メソ酒石酸より誘導されるイミンへの求核付加反応を活用する生理活性化合物の合成(ポスター発表の部)
• 光学活性1,2-ジアリール-1,2-ジアミノエタンおよび1,2-ジアリール-2-アミノエタノール合成への新しいアプロチ
• パン酵母による含硫黄環状ケトン類の立体選択的還元反応
• イミンと光学活性エステルの反応におけるジアステレオ面選択性の逆転現象
• 環境に調和する不斉パン酵母還元の硫黄化合物による基質特異性の改善
• 121(P66) 1β-メチルカルバペネムの効率的合成手法の開発(ポスター発表の部)
• β-ラクタム環構築における異なる金属種を用いる立体化学のスイッチング
• Mn(3)-ザ-レン錯体触媒による2重結合のエナンチオ選択的エポキシ化反応 (1995年の化学-5-)
• 19 3-ヘテロ置換β-ラクタム環合成における立体制御手法(口頭発表の部)
• 不斉合成における単一不斉源から両エナンチオマーの作り分け : イミンへの付加反応
• 40 β-ラクタム環合成における立体制御手法(口頭発表の部)

もっと見る 閉じる

スポンサーリンク