Organic Letters
Letter
coordination of the vinylarene18 and subsequent insertion into a
Ni−H bond to give organonickel intermediates; and (iii)
reductive elimination occurred to afford a branched product or a
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1
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In summary, we have synthesized a novel kind of heteroleptic
Ni(II) complex of the type Ni(NHC)[P(OR)3]Br2 (1−3) and
reported their application as the first Ni(II)-based precatalysts
for regioselectively-switchable hydroarylation of vinylarenes
with benzothiazoles in the presence of stoichiometric amounts
of magnesium turnings. The NHC-controlled regioselective
switch of the present mode is very rare in hydroarylations
reported thus far, which afforded a new practical protocol for the
synthesis of a wide variety of 2-alkylated benzothiazoles. The
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ligand and a phosphite ligand for the development of nickel
catalysis. Further fine-tuning of their catalytic performances by
surveying well-matched pairs of NHC/P(OR)3 ligands,
extension of this method to other substrates, and a detailed
mechanistic study are underway in our laboratory.
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ASSOCIATED CONTENT
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S
* Supporting Information
The Supporting Information is available free of charge on the
́
(11) Rull, S. G.; Rama, R. J.; Alvarez, E.; Fructos, M. R.; Belderrain, T.
Detailed experimental procedures, characterization data
for complexes 1−3, structural data for 1−3, and details
pertaining to the characterization of the products (PDF)
R.; Nicasio, M. C. Dalton Trans 2017, 46, 7603 and references cited. .
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Accession Codes
mentary crystallographic data for this paper. These data can be
contacting The Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
catalytic system involving Ni(COD)2, i.e., Ni(COD)2/IPr*OMe
/
NaOtBu, afforded higher yields of selected products in hydroarylations
of unactived alkenes. See: (b) Schramm, Y.; Takeuchi, M.; Semba, K.;
Nakao, Y.; Hartwig, J. F. J. Am. Chem. Soc. 2015, 137, 12215.
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(17) 31P NMR spectra of free P(OEt)3, Ni(IMes)[P(OEt)3]Br2,
Ni(IPr*OMe)[P(OEt)3]Br2, and the corresponding hydride intermedi-
ates indicated that the phosphite ligand P(OEt)3 possibly coordinated
AUTHOR INFORMATION
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Corresponding Author
ORCID
Notes
(18) A phosphite ligand substitution with styrene involved, see: Mo,
Z.; Xiao, J.; Gao, Y.; Deng, L. J. Am. Chem. Soc. 2014, 136, 17414.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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Dedicated to Professor Qi Shen on the occasion of her 80th
birthday. We are grateful to the National Natural Science
Foundation of China (Grant No. 21472134), the Key
Laboratory of Organic Chemistry of Jiangsu Province, and the
Priority Academic Program Development of Jiangsu Higher
Education Institutions (PAPD) for financial support.
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