Organic Letters
Letter
by methanol forms alkenylboronate intermediate E irreversibly.
In the second step, alkoxy exchange takes place between
intermediate E and methoxyborate A to form complex F
reversibly. Correspondingly, another nucleophilic addition also
could take place via transition state TS2 with a free energy
barrier of 20.6 kcal/mol with the activation of boryl group to
form a boraspiro intermediate G. The followed B−O bond
elimination could take place via transition state TS3 with a free
energy barrier of 24.3 kcal/mol to form an alkenylborate
intermediate H, which could be protonated to yield product 2.
Further computational and experimental studies for the
detailed mechanism of this transformation are underway.
The tetrasubstituted alkenylboronates are very important
synthetic intermediates; therefore, further transformation of 2d
was applied (Scheme 4). The Suzuki coupling of alkenylbor-
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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Financial support from the National Natural Science
Foundation (21772046 and 21772020), Program of Innovative
Research Team of Huaqiao University (Z14X0047), the
Recruitment Program of Global Experts (1000 Talents Plan),
the Natural Science Foundation of Fujian Province
(2016J01064), and Fundamental Research Funds for the
Central Universities (Chongqing University) (No.
2018CDXZ0002; 2018CDPTCG0001/4) is gratefully ac-
knowledged. We also thank the Instrumental Analysis Center
of Huaqiao University for analysis support. Z.K. thanks the
Subsidized Project for Cultivating Postgraduates’ Innovative
Ability in Scientific Research of Huaqiao University.
Scheme 4. Synthetic Application of Alkenylboronates
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lations, and H, C, and B NMR spectra (PDF)
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