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Chelation‐Assisted Rh I ‐Catalyzed ortho ‐Alkylation of Aromatic Ketimines or Ketones with Olefins
Author(s) -
Jun ChulHo,
Moon Choong Woon,
Hong JunBae,
Lim SungGon,
Chung KwanYong,
Kim YeonHee
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020118)8:2<485::aid-chem485>3.0.co;2-1
Subject(s) - alkylation , chemistry , benzylamine , tsuji–trost reaction , medicinal chemistry , catalysis , chelation , rhodium , reactivity (psychology) , metallacycle , selectivity , organic chemistry , allylic rearrangement , medicine , x ray crystallography , alternative medicine , physics , pathology , diffraction , optics
Described herein is the Rh I ‐catalyzed ortho ‐alkylation of aromatic ketimines or ketones with olefins. This method showed high reactivity and selectivity to monoalkylation for a variety of olefins including 1‐alkenes with an allylic proton, α , ω ‐dienes, and internal olefins. For a mechanistic study, H/D exchange experiments were carried out, which demonstrated that the ortho C−H bond could be easily cleaved even at the low temperature of 45 °C. The key step of this reaction is the formation of a stable five‐membered metallacycle by a chelation‐assisted ortho C−H bond activation. Furthermore, the direct ortho ‐alkylation of aromatic ketones with the Rh I complex was successfully achieved by adding 50 mol % of benzylamine as a chelation‐assistant tool.