N-ヘテロサイクリック・カルベン・ボランによる低電子芳香環の1,4-水酸化反応
Wen Dai1, Steven J Geib1, Dennis P Curran1
1Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15208, United States.
Journal of the American Chemical Society
|February 27, 2020
まとめ
N-ヘテロサイクルのカルベンボランは,芳香環で光レドックス反応を起こし,無芳香化ボリル化サイクロヘクサディエンを生成する. このプロセスは,提案されたラジカル媒介メカニズムを通じて,ステリカルに阻害された製品の形成を好む.
科学分野:
- 有機化学
- 写真化学
- オーガノボロン化学
背景:
- N-ヘテロサイクリックカルベンボラン (NHC-ボラン) は有機合成における多用途の反応剤である.
- フォトレドックス触媒は穏やかな条件下で新しい反応経路を可能にします.
- 電子が少ないアロマティックリングは,医薬品や材料の一般的なモチーフです.
研究 の 目的:
- フォトレドックス条件下でのNHCボランと貧乏な芳香環の反応を調査する.
- 脱オロマ化とボリレーションのメカニズムを解明する.
- 観察された製品の地域選択性を理解する.
主な方法:
- 可視光を用いたフォトレドックス触媒
- NHC-ボランが様々な電子が少ない芳香基質と反応する.
- 製品特性を示すために,光譜分析 (NMR,質量スペクトロメトリ) を行う.
- ラジカル捕獲実験を含むメカニズム研究 (暗示).
主要な成果:
- 脱オロマ化された3-NHC-ボリル-1,5-サイクロヘキサディエンが成功して合成された.
- 製品は公式には1,4-ヒドロボレーション反応から得られます.
- よりステリックに阻害された (二重オーソスチューテッド) 製品の地域選択的形成が観察されました.
- NHC-ボラン酸化,アロマティックリング還元,ラジカルカップリング,およびプロトネーションを含むメカニズムが提案されています.
結論:
- フォトレドックス触媒は,NHC-ボランと電子が少ないアロマティックから脱オロマ化されたボリル化サイクロヘクサディエンの効率的な経路を提供します.
- この反応は高い地域選択性を示し,固体的に要求される製品を好む.
- 提案された根基ベースのメカニズムは,観察された結果を説明し,NHC-ボランの反応性についての洞察を提供します.
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