Domino Michael/Retro-Michael/Mukaiyama-Aldol Reactions of 1,3-Bis-Silyl Enol Ethers with 3-Acyl- and 3-Formylbenzopyrylium Triflates - Synthesis of Functionalised 2,4′-Dihydroxybenzophenones

The reaction of 1,3‐bis‐silyl enol ethers with 3‐acyl‐ and 3‐formylbenzopyrylium triflates, which can be generated in situ from 3‐acyl‐ and 3‐formylchromones, affords a great variety of functionalised 2,4′‐dihydroxybenzophenones and 4‐(2‐hydroxybenzoyl)salicylates. These products are formed by a dom...

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Bibliographic Details
Published in:European Journal of Organic Chemistry 2006-08, Vol.2006 (16), p.3638-3644
Main Authors: Appel, Bettina, Rotzoll, Sven, Kranich, Remo, Reinke, Helmut, Langer, Peter
Format: Article
Language:English
Subjects:
Benzophenones
Chromones
Cyclisations
Domino reactions
Silyl enol ethers
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Summary:The reaction of 1,3‐bis‐silyl enol ethers with 3‐acyl‐ and 3‐formylbenzopyrylium triflates, which can be generated in situ from 3‐acyl‐ and 3‐formylchromones, affords a great variety of functionalised 2,4′‐dihydroxybenzophenones and 4‐(2‐hydroxybenzoyl)salicylates. These products are formed by a domino Michael/retro‐Michael/Mukaiyama‐aldol reaction. This methodology is successfully applied to the synthesis of novel UV‐A/B and UV‐B filters. Three 4‐(2‐hydroxybenzoyl)salicylic acids show a good in vitro activity in a selectin bioassay. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
ISSN:1434-193X
1099-0690
DOI:10.1002/ejoc.200600082