Beilstein J. Org. Chem.2026,22, 795–802, doi:10.3762/bjoc.22.61
-osaka, Osaka 577-0056, Japan 10.3762/bjoc.22.61 Abstract E-Selective bromination for diphenylacetylene was established by using the combination of NBS and FeBr3 in CH2Cl2. In addition, easy purificationandseparation from the crude product were found. When the crude product was treated with heptane
, the E isomer could be recovered as a solid material by utilizing the difference in solubility. On the other hand, the Z isomer could be removed by filtration while remaining in solution.
Keywords: bromination; diarylacetylenes; green chemistry; purificationandseparation; stereoselective reaction
interested in the selective synthesis of the E isomer of 1,2-dibromo-1,2-diphenylethylene, together with simple purificationandseparation toward process chemistry, because the compound is an attractive synthetic intermediate for further transformations. During the course of our studies, we have found that
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Graphical Abstract
Scheme 1:
Selected and previous reports for bromination of diphenylacetylenes (a–c), and this work (d).
Beilstein J. Org. Chem.2013,9, 2564–2569, doi:10.3762/bjoc.9.291
employing gold(I) catalysis [44], which after purificationandseparation afforded the expected products in 41% and 31% yields, respectively. The dihydrofurans 14 and 15 are more stable than the allenyl alcohols 12 and 13 and therefore allowed smooth separation by HPLC. At this point, the assignment of the
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Graphical Abstract
Scheme 1:
Structure of jaspine B 1 and its stereoisomers 2–4.