グリコシルドナーの反応性をサルフォナート脱出グループ能力にマッチングすると,SN2のグリコシル化が可能になる
Ming-Hua Zhuo1, David J Wilbur1, Eugene E Kwan2
1Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States.
Journal of the American Chemical Society
|September 26, 2019
まとめ
高度に選択的なβ-グリコシレーション反応は,スルフォニル塩化活性化剤とグリコシールドナーをマッチすることで達成される. この方法は,SN2のようなメカニズムに依存し,炭水化物の合成におけるステレオ制御のための伝統的な保護群を回避します.
科学分野:
- 炭水化物の化学
- 有機合成
- ステレオ選択反応
背景:
- オリゴサッカライド合成は,ステレオ制御のための保護グループに依存する.
- グライコシレーションにおいて高いβ選択性を達成することは,依然として課題である.
- 既存の方法は,敏感な機能群と互換性がないかもしれません.
研究 の 目的:
- 高度に選択的なβグリコシル化反応のための新しい戦略を開発する.
- 酸や塩基に敏感な保護グループに頼らずにステレオ制御を実現する.
- 観察されたβ選択性の背後にあるメカニズムを明らかにする.
主な方法:
- 硫酸塩活性化剤とグリコシルドナー・ヘミアセタルの電子が一致する.
- SN2のようなメカニズムを用いて,α-グリコシルアリルスルフォナートのステレオインバーションを行う.
- 核磁気共振 (NMR) のスペクトロスコーピーを用いる.
- 運動同位体効果 (KIE) を測定する.
- 密度関数理論 (DFT) の計算を実行する.
主要な成果:
- 非常に選択的なβグリコシル化反応が示された.
- 酸と塩基に敏感な常用保護群との互換性を示した.
- β-選択性の源としてα-グリコシルアリルルフォナートのステレオインバーションを特定した.
- 機械学的研究はSN2のような経路を支持した.
結論:
- グライコシレーションでβ選択性を達成するための新しい方法が確立されています.
- この戦略は,従来のグループ依存の保護方法の代替案です.
- この発見は,ステレオ選択的グリコシレーションのより深いメカニズム的理解を提供します.
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