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Organic & Biomolecular Chemistry
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COMMUNICATION
under basic conditions. A variety of 2-DaOmI:in10o.c10h3a9lc/Co7nOeBs01w53e6rDe
successfully converted to their corresponding 3-acylindoles at
moderate to high yields. This method was then applied to
realize a rapid and high-yielding synthesis of SCB01A.
Acknowledgements
This work was generously supported by Grant-in-Aid for Young
Scientists (B) (15K18840) from the Japan Society for the
Promotion of Science (JSPS) and also by the MEXT-Supported
Program for the Strategic Research Foundation at Private
Universities, 2014–2018 (S1411037).
Scheme 2 The plausible mechanism
Notes and references
Increasing the electron density on the migrating aryl group was
less effective, with 3j obtained in 74% yield.
1
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On the basis of previous literatures,10,11 a possible reaction
mechanism was described in Scheme 2. First, the electrophilic
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addition of PhI(OAc)2, activated by BF3
the double bond would furnish the adduct
rearrangement was assisted by the lone pair of oxygen and the
aryl moiety migrated to generate the oxonium intermediate
・
OEt2,12 and MeOH to
. Oxidative
A
B,
which was converted to the corresponding acetal by the
addition of MeOH. Under basic conditions, the deprotection of
2
N-COCF3 group and elimination of methoxy group generated
C
and then subsequent cyclization and aromatization afforded 3-
acylindoles.
Finally, the developed method was applied to the synthesis
of SCB01A, which was synthesized by Friedel-Crafts reaction in
the previous reports3a,6e (Scheme 3). Synthesis of the chalcone
was initiated from the reduction of
corresponding amine, which was then treated with
trifluoroacetic anhydride to afford in 72% yield. Wittig
reaction of with ylide produced chalcone in 98% yield.
4, providing the
5
3
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H.-Y. Lee, J.-F. Lee, S. Kumar, Y.-W. Wu, W.-C. HuangFu, M.-J.
Lai, Y.-H. Li, H.-L. Huang, F.-C. Kuo, C.-J. Hsiao and C.-C.
Cheng, Eur. J. Med. Chem., 2017, 125, 1268.
5
6
7
The final step, production of SCB01A from chalcone 7, under
the optimized, one-pot conditions described herein
successfully resulted in SCB01A in 95% yield.
Conclusions
We have developed a concise one-pot synthesis of 3-acylindole
derivatives from N-COCF3 protected 2-aminochalcone via
4
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5451; (b) A. R. Katritzky, K. Suzuki, S. H. Singh, and H.-Y. He, J.
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Scheme 3 Synthesis of SCB01A
5
6
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