Organic Letters
Letter
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16) Other reductants such as PMHS or Et SiH were evaluated but
́
A.; Graham,
(
3
found to provide limited reactivity.
(
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(21) DDQ was the best alternative oxidant we found, providing
indole 3 in an optimized 91% ee. Catalytic Mn oxidation systems such
as Mn(OAc) were investigated in conjunction with various oxidants
2
but were found to suffer from significant racemization.
(
22) See the Supporting Information for details on the synthesis of
imidazole 12.
23) A number of additives were evaluated in the Suzuki coupling to
(
mimic the effect of the crude borylation stream, including methanol,
pinacol, and inorganic salts; however, no single additive evaluated to
date replicates this phenomenon.
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dx.doi.org/10.1021/ol500971c | Org. Lett. 2014, 16, 2310−2313