Organic Letters
Letter
Scheme 6. Possible Reaction Mechanism
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
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ORCID
Author Contributions
†M.-J.X. and H.H. contributed equally.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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We thank the National Key Research and Development
Program (2016YFA0202900), the Science and Technology
Commission of Shanghai Municipality (18XD1405000), the
Strategic Priority Research Program of the Chinese Academy of
Sciences (Grant No. XDB20000000), and Shanghai Institute of
Organic Chemistry (sioczz201807) for financial support.
allylcopper 17 (the stereochemistry was not known), and both
of these intermediates might be stabilized by the cyano group.
(
E)-Allylcopper 15 might isomerize to allylcopper 17 through a
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REFERENCES
π-allylcopper intermediate 16 derived from η −η interconver-
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1
8
sion. Nucleophilic attack of the allylcopper moiety in 17 to
the cyano group, followed by transmetalation, gives an
iminoboron intermediate 19 and regenerates the copper
catalyst. Hydrolysis and aromatization of 19 deliver the final
product 2. The challenging issue in borylcupration of allenes
lies in the regioselectivity. Copper-catalyzed borylation of
allenes has been studied by various groups such as Tsuji, Ma,
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5
(
(
1
9
and Hoveyda, However, the high regioselectivity leading to
allyl copper species was observed mainly with terminal allenes.
The results shown in the borylation of intermediate 9 indicates
that π-allyl copper species could also be selectively formed from
internal 1,3-diaryl-substituted allenes.
In summary, we have developed a copper-catalyzed
borylative cyclization of o-(cyano)phenyl propargyl carbonates,
which provides a highly substituted 3-boryl-1-naphthylamines
with excellent regioselectivity and wide functional group
compatibility. The resulting products have been applied for
the synthesis of functionalized 1-naphthylamines via oxidation
or coupling reactions. The reaction likely proceeds through the
generation of allenyl boronates via copper-catalyzed borylation
of propargyl carbonates, followed by cascade deborylation/
borylcupration and cyclization reactions. Further applications of
this cascade reaction to the synthesis of diverse complex
molecules are currently underway.
3
(
4
(
1
̈
̈
(
9
(
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ASSOCIATED CONTENT
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Supporting Information
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2
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e) Zhong, C.; Kunii, S.; Kosaka, Y.; Sawamura, M.; Ito, H. J. Am.
Chem. Soc. 2010, 132, 11440.
crystallographic data for this paper. These data can be obtained
(8) Zhang, L.; Cheng, J.; Carry, B.; Hou, Z. J. Am. Chem. Soc. 2012,
134, 14314.
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