A concise synthetic approach to brazilin via Pd-catalyzed allylic arylation

A short synthetic route to the trimethyl ether of brazilin was developed in 6 steps from 7-methoxychromene with 78% overall yield. Regioselective installation of a formyl group onto 7-methoxychromene followed by reduction and acetylation afforded allylic acetate. Palladium-catalyzed allylic coupling...

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Bibliographic Details
Published in:	Organic & biomolecular chemistry Vol. 13; no. 14; p. 4331
Main Authors:	Jung, Youngeun, Kim, Ikyon
Format:	Journal Article
Language:	English
Published:	England 14-04-2015
Subjects:	Acetates - chemistry Allyl Compounds - chemistry Benzopyrans - chemical synthesis Benzopyrans - chemistry Catalysis Chemistry Techniques, Synthetic Cyclization Palladium - chemistry
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Summary:	A short synthetic route to the trimethyl ether of brazilin was developed in 6 steps from 7-methoxychromene with 78% overall yield. Regioselective installation of a formyl group onto 7-methoxychromene followed by reduction and acetylation afforded allylic acetate. Palladium-catalyzed allylic coupling of allylic acetate with arylboronic acid provided direct access to 3-benzylchromene which was converted to the target molecule upon ensuing dihydroxylation and acid-catalyzed cyclization in a highly concise manner.
ISSN:	1477-0539
DOI:	10.1039/c5ob00216h