Farhi J, Rezgui SP, Yu H, Stoltz BM. Synthesis of the Pentacyclic Core of Sanguinone B Enabled by Alkyne Functionalization.
Org Lett 2025;
27:5390-5393. [PMID:
40372280 DOI:
10.1021/acs.orglett.5c01332]
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Abstract
Sanguinones A and B are recently isolated pyrroloiminoquinone alkaloids possessing a rare C4 carboxylic acid. We report a synthetic approach toward the full carbon and nitrogen pentacyclic core of sanguinone B, with the correct oxidation at C4. Highlights of this approach include the application of a Larock/Buchwald-Hartwig annulation cascade to access a key tricyclic intermediate and alkyne functionalization using Rh(I) or Cu(I) catalysis to access hindered benzylic ketones.
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