自由な (NH) -ヘテロアーレンの選択的C-アリレーションは,触媒C-H結合機能化によるものです
1Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Journal of the American Chemical Society
|May 2, 2003
まとめ
新しいパラジウム触媒システムにより,様々な自由 (NH) -ヘテロアーレンの直接アリレーションが可能になり,高いC-アリレーション選択性が得られます. この方法は,保護と脱保護のステップを回避することによって,合成を簡素化します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- ヘテロサイクル化学 ヘテロサイクル化学
背景:
- パラジウムによって触媒化されたクロスカップリング反応は,有機合成において極めて重要です.
- 直接アリレーションは,従来の方法よりも,より原子経済的で効率的な代替手段を提供します.
- アリル置換ヘテロアレンの合成には,保護/脱保護を含む多段階の手順がしばしば必要です.
研究 の 目的:
- 幅広い自由 (NH) -ヘテロアーレンの直接アリレーションのための新しいパラジウム触媒システムを開発する.
- 高い地域選択性,特にC-arylationを達成するために,N-arylationとbis-arylationを回避します.
- 合成ステップの数を減らすことにより,アリル-NH-ヘテロアーネスの合成を効率化します.
主な方法:
- パラジウム触媒による直接アリレーション反応.
- パラジウム触媒,トリフェニルフォスフィンリガンド,および酸化マグネシウム (MgO) 塩基を含むシステムを利用しました.
- 銅(I) ヨウ化物 (CuI) のような添加物の地域選択性に対する影響を調査した.
主要な成果:
- インドル,ピロール,ピラゾール,イミダゾール,ベンジミダゾール,ピュリンを含む,自由な (NH) -ヘテロアーレンの幅広いスペクトルを成功裏にアライレートしました.
- MgOをベースとして使用した単一のC-アリレーションの有意な選択性を達成し,N-アリレーションまたはビス-アリレーションは観察されなかった.
- イミダゾールアリレーションにおける地域選択性を,CuI.を追加することによって,C-4からC-2に切り替える能力を示した.
結論:
- 開発されたパラジウム触媒系は,自由 (NH) -ヘテロアレンを直接C-アリレーションするための効率的で選択的な方法を提供します.
- この直接アリレーションアプローチは,合成経路を大幅に簡素化し,従来の方法と比較して3つのステップを排除します.
- このシステムは,効率の向上と廃棄物の削減により,多様なアリル-NH) ヘテロアレンにアクセスするための貴重なツールを提供します.
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