Mechanistic Investigations of Reactions of the Frustrated Lewis Pairs (Triarylphosphines/B(C6F5)3) with Michael Acceptors
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Published on: February 20, 2020
Jonathan Dupré1, Annie-Claude Gaumont1, Sami Lakhdar1
1Normandie Université, Laboratoire de Chimie Moléculaire et Thio-organique, CNRS-UMR 6507, ENSICAEN, Université de Caen Normandie, 6, Boulevard du Maréchal Juin, Caen 14000, France.
Abstract:
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.
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