Organic Letters
Letter
We have established a new catalytic cycle with high
performance for site-selective acylation. We supposed that
acylpyridinium carboxylate A′ (Figure 1c) generated by in situ
counteranion exchange would be the reactive intermediate.
However, the possibility that A′ was generated by the reaction
between the catalyst and a mixed anhydride formed by the acyl
chloride and carboxylate5c could not be eliminated, since the
mixed anhydride was often obtained as a side product in the
present method. In order to examine this possibility, a mixed
anhydride was independently prepared from BzCl, PivOH, and
DIPEA and used for the catalytic site-selective acylation of 2
(Scheme 1). Only a trace amount of the 4-O-acylate was obtained
ACKNOWLEDGMENTS
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This research was financially supported by Grants-in-Aids for
Scientific Research (S) (JP26221301), Young Scientists (B)
(JP15K18827), and Scientific Research on Innovative Areas
“Advanced Molecular Transformations by Organocatalysts”
(JP23105008) and “Middle Molecular Strategy”
(JP16H01148). A.I. acknowledges the financial support through
JSPS Research Fellowships for Young Scientists (JP15J10954).
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Scheme 1. Attempted Acylation of 2 with a Mixed Anhydride
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are required for the completion of the acylation. This is because
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ASSOCIATED CONTENT
* Supporting Information
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S
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The Supporting Information is available free of charge on the
Details of NMR experiment, kinetic studies, experimental
procedures, analytical data, and copies of the new products
AUTHOR INFORMATION
Corresponding Authors
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3974. (e) Wurz, R. P. Chem. Rev. 2007, 107, 5570. (f) Muller, C. E.;
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ORCID
Schreiner, P. R. Angew. Chem., Int. Ed. 2011, 50, 6012. (g) Pellissier, H.
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Notes
The authors declare no competing financial interest.
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Org. Lett. XXXX, XXX, XXX−XXX