1,3(Z) -ペンタディエンの1,5-水素シフトにおけるフェニルによる混乱. もう一つのカメレオン的な移行地域?
William von E Doering1, Edmund J Keliher, Xin Zhao
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138-2902, USA. doering@chemistry.harvard.edu
Journal of the American Chemical Society
|October 28, 2004
まとめ
フェニル置換剤は1,5-デニル水素シフト反応を加速する. この過激な安定効果は,ペンタジーン系内の異なる位置で観察され,活性化エネルギーに影響を与えました.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 反応メカニズム 反応メカニズム
- コンピューティング・ケミストリー
背景:
- 1,5-デニル水素シフトは,重要な有機反応である.
- 反応速度に対する置換物の効果を理解することは,合成化学にとって極めて重要です.
研究 の 目的:
- 非循環的1,5-ディエニル水素シフトに対するフェニル置換物の影響を調査する.
- 様々な位置でのフェニル群の根幹安定効果を定量化するために.
主な方法:
- アクティベーションエネルギーを計算するために,計算化学の方法が採用されました.
- この研究では,アサイクロンおよびサイクロンアナログを含む1,3 (((Z) -ペンタディエンの置換系を調査した.
- 必要に応じて熱化学的補正が施された.
主要な成果:
- フェニル置換剤は1,5-デニル水素シフトを著しく加速する.
- 1-フェニル-5-p-トリル誘導体は,5.8 kcal mol (−1) より低い活性化エネルギーを示した.
- 2と3の位置にあるフェニル基も安定化作用を及ぼした (3.6と3.4 kcal mol(-1)).
結論:
- フェニル置換剤は,1,5-デニル水素シフトの移行状態を安定させる.
- 観測された効果は,反応の移行領域の"カメレオン"モデルを支持する.
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