マロニックアンヒドリドの分解

Charles L Perrin¹, Agnes Flach, Marlon N Manalo

¹Department of Chemistry, University of California-San Diego, La Jolla, California 92093-0358, USA. cperrin@ucsd.edu

Journal of the American Chemical Society

|May 26, 2012

まとめ

マロンのアンヒドリドはケテンと二酸化炭素に分解する. メチルマロンのアンヒドリドは,活性化エネルギーが低いため,最も早く分解するが,ディメチルマロンのアンヒドリドは最もゆっくり分解する.

科学分野:

有機化学オーガニック・ケミストリー
化学動力学化学動力学

背景:

マロニックアンヒドリドは,容易に分解することが知られている.
それらの分解メカニズムを理解することは,合成化学にとって極めて重要です.

研究の目的:

マロニク,メチルマロニク,およびディメチルマロニクアンヒドリドの熱分解運動を調査する.
分解速度とメカニズムに影響を与える要因を解明する.

主な方法:

速度定数は,核磁共振 (NMR) 光譜を用いて測定した.
アクティベーションパラメータは,速度定数の温度依存から決定された.
機械的な解釈をサポートするために,計算的方法が採用されました.

主要な成果:

メチルマロニックアンヒドリドは,最も速い分解率を示した.
ディメチルマロニクアンヒドリドは分解速度が最も遅かった.
分解速度がメチル群の数に非線形的に依存していることが観察されました.

結論:

分解は,協調したサイクロレバーションメカニズムによって行われます.
計算データで裏付けられた,歪んだ移行状態構造が提案されています.
置換パターンは分解経路と動力学に大きな影響を及ぼします.

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