514
N. A. Morra, B. L. Pagenkopf
PAPER
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Acknowledgment
We thank NSERC and The University of Western Ontario for finan-
cial support of this work.
(13) NMR analysis of the mixture showed the regeneration of
BF3·OEt2 as well as peaks tentatively assigned to
BF(OTf)2·OEt2, and B(OTf)3·OEt2: 1H NMR showed two
new etherate peaks downfield of BF2OTf·OEt2 [d = 4.74 (q,
J = 7.0 Hz, 4 H), 1.65 (t, J = 7.0 Hz, 6 H), and 4.61 (q,
J = 6.9 Hz, 4 H), 1.60 (t, J = 6.9 Hz, 6 H)]. 11B NMR
showed two new singlets upfield of the BF2OTf·OEt2 (d =
–1.54, –2.28). 19F NMR showed two new singlets in the
triflate region (d = –75.47, –7.40).
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Synthesis 2008, No. 4, 511–514 © Thieme Stuttgart · New York