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

摘要

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-hydroxyben-zoyl) salicylic acids show a good in vitro activity in a selectin bioassay.