ダイアルキルエーテルの形成 高値ニッケル
Franck Le Vaillant1, Edward J Reijerse2, Markus Leutzsch1
1Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany.
Journal of the American Chemical Society
|November 4, 2020
まとめ
この研究では,ヨウ素 (I2) がニッケル触媒によるエーテル合成において,C (sp3) -OC (sp3) 結合を直接形成しないことが明らかになった. 安定したニッケル (III) 中間物質は,好ましくC (sp3) -I結合を形成し,周期的なエーテル形成を可能にします.
科学分野:
- 有機金属化学
- カタリシス
- 有機合成
背景:
- I2 誘発の周期性ダイアルキルエーテル形成を6基のオキサニケラサイクルから調査した.
- 以前の報告では,C ((sp3) -OC ((sp3)) 結合の直接的な形成が,還元的な除去によって示唆されていた.
研究 の 目的:
- I2誘発のサイクルダイアルキルエーテル形成のメカニズムを解明する.
- 反応性中間物質を特定し,触媒サイクルにおけるヨウ素の役割を理解する.
主な方法:
- 顕微鏡 (NMR,EPR) と結晶学的分析を用いた詳細なメカニズム調査.
- パラマグネティックバイメタリックNi (III) 中間物質の分離と特徴付け.
- 中間物質の熱分解試験を様々な温度で行う.
主要な成果:
- 安定した,パラマグネティックバイメタリックのNi (III) 介質は,Ni2 (OR) 2コアとμ-イオドブリッジで分離され,特徴づけられました.
- 中間物質は -10 °C以上で分解し,除去製品とイオドアルカノールを生成し,好ましいC ((sp3) -I結合の還元性除去を示します.
- サイクルTHFリング形成は,アルコール/アルコキシドをC ((sp3) -I結合にサイクルすることによって発生する.
結論:
- I2を用いた還元性除去による直接のC ((sp3) -OC ((sp3)) 結合形成は機能しない可能性が高い.
- F+酸化剤を使用することで,高価ニッケル中心でC ((sp3) -OC ((sp3)) 結合形成を阻害し,副作用を最小限に抑えることができます.
- この研究により,以前はニッケル触媒に困難であった,還元性除去によるディエチルエーサーの合成が可能になった.
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