Organic Letters
Letter
Scheme 6. Proposed Reaction Mechanism
ACKNOWLEDGMENTS
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Financial support by the National Natural Science Foundation of
China (21272115) and Natural Science Foundation of Jiangsu
Province (No. BK20161494) is greatly appreciated.
REFERENCES
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Scheme 7. Synthesis of a Biologically Active Molecular
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tion of 9 afforded the product 10, which was further converted to
the desired product 11 via SNAr reaction.
In summary, we have demonstrated the design and synthesis of
a new type of Cp*Ir complex bearing a 2,2′-bibenzimidazole
ligand and developed it as a highly effective and general catalyst
for the N-methylation of a variety of amines with methanol in the
presence of a weak base (0.3 equiv of Cs2CO3).
(13) As one of the reviewers suggested, reactions of 7a−e with 2 were
performed at lower temperature (60 °C). It was found that products
were generated in <10% yields.
ASSOCIATED CONTENT
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(14) The stoichiometric reaction of cat. 1 with a base (Cs2CO3) was
performed in 120 °C for 12 h to afford an unidentifiable mixture by the
analysis of 1H NMR spectra. It was supposed that species A with a vacant
site is not stable.
S
* Supporting Information
Experimental procedures and characterization data, and a CIF
file giving crystallographic data. The Supporting Information is
(15) A peak (δ −11.45) of [Ir-H] (species C) was observed in the 1H
NMR spectrum in the reaction of cat. 1 with 2. It was speculated to be a
characteristic signal of [Ir-H] (species C), see the Supporting
Experimental procedures and characterization data (PDF)
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X-ray data for the Cp*Ir catalyst (CIF)
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L. J. Med. Chem. 2015, 58, 7431.
AUTHOR INFORMATION
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Corresponding Author
ORCID
Notes
The authors declare no competing financial interest.
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Org. Lett. XXXX, XXX, XXX−XXX