ヴィニラジリジンにアイソシアネートのダイナミック・キネティック・アシンメトリック・サイクロアディションを添加する
Barry M Trost1, Daniel R Fandrick
1Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA. bmtrost@stanford.edu
Journal of the American Chemical Society
|September 25, 2003
まとめ
この研究では,ヴィニラジリジンとイソシアナートを使用して,パラジアム触媒による非対称変換を導入し,新しい化学合成のための特定のキラルリガンドと酸性コカタリストで高いエナチオセレクティビティ (ee) を達成します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- アシンメトリック・カタリシス
- 有機金属化学 有機金属化学
背景:
- 動的運動非対称変換は,キラル分子への効率的な経路を提供します.
- パラジウム触媒は,C-N結合形成のための強力なツールです.
- ビニラジリジンは,汎用性の高い合成中間物質です.
研究 の 目的:
- ラセミク・ヴィニラジリジンのパラジアム触媒化ダイナミック・キネティック・アシンメトリック変換の最初の例を調査する.
- イソシアネートにビニラジリジンを添加することで,高いエナンチオセレクティブ性のための反応条件を最適化するために.
主な方法:
- トランス-1,2-ダイアミノサイクロヘキサンおよびフォスフィノナフト酸/ベンゾ酸から派生したものを含むキラルリンガンドのスクリーニング.
- さまざまなコカタリストの調査,pKaは約4.7.7の酸に焦点を当てた.
- アジリジンにおける異なるアイソシアネート電友性およびN置換物の評価.
主要な成果:
- trans-1,2-diaminocyclohexaneと2-diphenylphosphino-1-naphthoic acidから派生したキラルリガンドは優れた性能を示した.
- pKa ~4.7 のエセティック酸やヒドロキシベンゾトリアゾールのような酸は,高いエナティオメール過量 (ee) を達成するために不可欠でした.
- 電子性少ないイソシアネートとN-ベンジル/アリラジリジンは,よりよい結果をもたらし,三次性C-N結合形成の比較可能な効果を示した.
結論:
- この研究では,ヴィニラジリジンを使用した非対称合成のための効果的なPd触媒法が確立されました.
- 観測された反応性は,ダイナミックなpi-allylパラジウム中間物質を含むカートン-ハメットシナリオと一致しています.
- その結果生成される製品は,すぐに価値あるイミダゾリジンと近隣のダイアミンに変換されます.
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