Hydroaminomethylation of Styrene Catalyzed by Rhodium Complexes Containing Chiral Diphosphine Ligands and Mechanistic Studies: Why Is There a Lack of Asymmetric Induction? - INSA Toulouse - Institut National des Sciences Appliquées de Toulouse Access content directly
Journal Articles ACS Catalysis Year : 2014

Hydroaminomethylation of Styrene Catalyzed by Rhodium Complexes Containing Chiral Diphosphine Ligands and Mechanistic Studies: Why Is There a Lack of Asymmetric Induction?

Abstract

Various chiral diphosphine ligands (P–P) have been introduced in the coordination sphere of neutral or cationic rhodium complexes, and the generated species catalyze efficiently the hydroaminomethylation reaction of styrene with piperidine. The diphospholane ligand family is particularly adapted to this tandem reaction leading to the branched amine with good chemo- and regioselectivity. We analyzed in detail the main reasons why the reaction proceeds with no enantioselectivity. Catalytic and HP-NMR experiments reveal the presence of the [Rh(H)(CO)2(P–P)] species as the resting state. DFT calculations allow us to elucidate the mechanism of the hydrogenation of the branched (Z) or (E)-enamine. From the [Rh(H)(CO)(P–P)] active species, the coordination of the two enamine isomers, the hydride transfer, the H2 activation, and then the final reductive elimination follow similar energetic pathways, explaining the lack of enantioselectivity for the present substrates. Analysis of the energy-demanding steps highlights the formation of the active species as crucial for this rate-limiting hydrogenation reaction.
No file

Dates and versions

hal-01969481 , version 1 (04-01-2019)

Identifiers

Cite

Delphine Crozet, Christos E. Kefalidis, Martine Urrutigoity, Laurent Maron, Philippe Kalck. Hydroaminomethylation of Styrene Catalyzed by Rhodium Complexes Containing Chiral Diphosphine Ligands and Mechanistic Studies: Why Is There a Lack of Asymmetric Induction?. ACS Catalysis, 2014, 4 (2), pp.435-447. ⟨10.1021/cs400906b⟩. ⟨hal-01969481⟩
33 View
0 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More