Hydrogen Activation by an Aromatic Triphosphabenzene

Lauren E. Longobardi, Chris Russell, Michael Green, Nell S. Townsend, Kun Wang, Arthur J. Holmes, Simon B. Duckett, John E. McGrady, Douglas W. Stephan*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

53 Citations (Scopus)

Abstract

Aromatic hydrogenation is a challenging transformation typically requiring alkali or transition metal reagents and/or harsh conditions to facilitate the process. In sharp contrast, the aromatic heterocycle 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene is shown to be reduced under 4 atm of H-2 to give [3.1.0]bicylo reduction products, with the structure of the major isomer being confirmed by X-ray crystallography. NMR studies show this reaction proceeds via a reversible 1,4-H-2 addition to generate an intermediate species, which undergoes an irreversible suprafacial hydride shift concurrent with P P bond formation to give the isolated products. Further, para-hydrogen experiments confirmed the addition of H-2 to triphosphabenzene is a bimolecular process. Density functional theory (DFT) calculations show that facile distortion of the planar triphosphabenzene toward a boat-conformation provides a suprafacial combination of vacant acceptor and donor orbitals that permits this direct and uncatalyzed reduction of the aromatic molecule.

Original languageEnglish
Pages (from-to)13453-13457
Number of pages5
JournalJournal of the American Chemical Society
Volume136
Issue number38
Early online date10 Sep 2014
DOIs
Publication statusPublished - 24 Sep 2014

Structured keywords

  • BCS and TECS CDTs

Keywords

  • CATIONIC RHODIUM COMPLEXES
  • MAIN-GROUP ELEMENTS
  • HOMOGENEOUS HYDROGENATION
  • SELECTIVE HYDROGENATION
  • DIHYDROGEN COMPLEXES
  • MOLECULAR-HYDROGEN
  • ASYMMETRIC HYDROGENATION
  • TRANSITION-METALS
  • CATALYSTS
  • OLEFINS

Cite this