Crabtree et al. have reported a DFT study on iridium catalysed
alkylation of amines with alcohols and shown that the amine
dissociation is the rate determining step in this process.8 The
ancillary carbonate ligand on iridium is shown to be involved in
the hydrogen transfer. As a result, higher temperatures are required
to achieve good rates for N-alkylation. Complementary to these
results we found that optimum yields of N-alkylated products were
achieved using elevated temperatures and potassium carbonate as
base. Furthermore, no C-alkylation was observed under optimized
N-alkylation conditions.
In summary 20-aminoacetophenone was successfully alkylated
with a range of substituted benzyl, heteroaryl alcohols to afford
either the corresponding C- or N- alkylated products in good
yield. Further studies to expand the application of the synthetic
strategy using diols are currently underway.
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We thank Prof Chris Rayner, Dr Andrew Wilson and Leeds
University for support.
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This journal is The Royal Society of Chemistry 2012
Chem. Commun., 2012, 48, 4701–4703 4703