Unprecedented halide dependence on catalytic asymmetric hydrogenation of 2-aryl- and 2-alkyl-substituted quinolinium salts by using ir complexes with difluorphos and halide ligands

Hiroshi Tadaoka, Damien Cartigny, Takuto Nagano, Tushar Gosavi, Tahar Ayad, Jean Pierre Genêt, Takashi Ohshima, Virginie Ratovelomanana-Vidal, Kazushi Mashima

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)

Abstract

The first highly enantioselective hydrogenation of 2-arylquinolinium salts by using cationic dinuclear iridium (III) halide complexes with difluorphos and some atropisomeric chiral diphosphine ligands as catalyst precursors has been reported. Asymmetric hydrogenation by using chiral transitionmetal complexes represents one of the cleanest and most environmentally benign processes available for producing optically pure organic compounds. The conversions were determined by H NMR spectroscopic analysis of the crude product. The new catalyst system also successfully converted 2-alkylquinolinium salts to the corresponding tetrahydroquinolines with excellent enantioselectivities. This catalysis is the unexpected superiority of chloro- and bromo-iridium catalysts over the corresponding iodo-iridium catalyst, which is opposite to the halide effect.

Original languageEnglish
Pages (from-to)9990-9994
Number of pages5
JournalChemistry - A European Journal
Volume15
Issue number39
DOIs
Publication statusPublished - Oct 5 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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