ケトンとチオケトンのアルキルリチウムとの対照反応:協調された実験と計算による調査
William F Bailey1, Ashley L Bartelson, Kenneth B Wiberg
1Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, USA. william.bailey@uconn.edu
Journal of the American Chemical Society
|January 17, 2012
まとめ
オルガノリチウムとチオケトンとの反応は,ケトンと著しく異なる. ケトンは添加されるが,アダマンタンタンチオンのようなチオケトンは主に硫黄によるチオルを産生する.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 有機金属化学 有機金属化学
背景:
- オーガノリチウムとのケトン反応は,通常,カルボニル基への核愛性添加を含みます.
- オーガノリチウムとのチオケトンの反応はあまり理解されていないが,添加は些細であるが,多様な製品を生成する.
研究 の 目的:
- オーガノリチウムとアダマンタンタンチオンの反応を徹底的に調査する.
- オーガノリチウムによるケトンとチオケトン反応のメカニズム的な違いを解明する.
主な方法:
- アダマンタンテニオンのメチル,n-ブチル,および tert-ブチルリチウムとの反応を研究した.
- 計算モデリング (B3LYP/6-311+G*) を採用し,加法および還元反応の移行状態を分析した.
- 計算分析のためのモデル基板としてアセトンとチオアセトンを使用した.
主要な成果:
- アダマンタンテニオンのn-ブチルリチウムと tert-ブチルリチウムとの反応は,主に2-アダマンタンテニオールを生成します.
- 計算による研究では,C=O対C=S結合へのオーガノリチウム添加の異なった移行状態が明らかになり,チオケトンへの添加が遅くなったことが説明されました.
- オーガノリチウムによるチオケトンの減少は,ケトンと比較してより低い活性化エネルギーを持つよりエクソテルミックです.
結論:
- 二価硫黄のユニークな電子およびステリック特性は,チオケトンとのオーガノリチウムの反応性に影響します.
- オーガノリチウムとチオケトンおよびケトンの反応経路は,移行状態のエネルギーと幾何学の違いのために著しく異なる.
- また,これらの反応において,ラジカル媒介経路が役割を果たす可能性もあります.
関連する概念動画
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