Organic Letters
Letter
of 4a to be 35% ee and that of rearranged product 3a to be 0%
ee (Scheme 2). The low residual enantiomeric excess of 4a can
ASSOCIATED CONTENT
* Supporting Information
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S
Contains experimental and compound characterization details
and copies of spectra of isolated products. This material is
Scheme 2. Rearrangement of Enantioenriched (R)-4a to 3a
AUTHOR INFORMATION
Corresponding Author
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Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
J.W. thanks the National Science Foundation (CAREER CHE-
1052824) and Dartmouth College for financial support.
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REFERENCES
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stereochemical information has been deleted. Alkylation at
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thermodynamically preferred, hydroamination product 3a.
We then showed that N-alkylation products are, in fact, not
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exclusively at sulfur in excellent yields (Table 2). These results
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Table 2. PT-thiol Alkylation at Sulfur
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underscore the complementary nature of our hydroamination
process as compared to alkylation of 1 with halide-based
electrophiles.
In summary, we have demonstrated the feasibility of carrying
out formal hydroamination reactions between styrenes and 1
under Ga(OTf)3 catalysis. The resulting tetrazoline-5-thione is
a unique heterocyclic scaffold that is of interest for its
demonstrated biological and insecticidal activity. We have
also elucidated a probable mechanistic pathway in which we
show that the reaction likely proceeds through a kinetically
favored hydrothiolation event, which then undergoes rearrange-
ment to the thermodynamically preferred formal hydro-
amination products.
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dx.doi.org/10.1021/ol5020416 | Org. Lett. XXXX, XXX, XXX−XXX