Mechanistic Investigations of Reactions of the Frustrated Lewis Pairs (Triarylphosphines/B(C6F5)3) with Michael Acceptors

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• 作者：Jonathan Dupré ; Annie-Claude Gaumont ; Sami Lakhdar
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：February 3, 2017
• 年：2017
• 卷：19
• 期：3
• 页码：694-697
• 全文大小：323K
• ISSN：1523-7052

文摘

Frustrated Lewis pair (FLP)-catalyzed reduction of Michael acceptors is a challenging reaction that proceeds with specific FLP structures. Kinetics and equilibrium of the reactions of two phosphines (Ar₃P), namely tri(1-naphthyl)phosphine and tri(o-tolyl)phosphine, are reported with reference electrophiles. The reason for the failure of the FLPs (Ar₃P/B(C₆F₅)₃) to reduce activated alkenes under H₂ pressure is shown to be a hydrophosphination process that inhibits the reduction reaction. Kinetic and thermodynamic factors controlling both pathways are discussed in light of Mayr’s free linear energy relationships.