An efficient methodology to substituted furans via oxidation of functionalized α-diazo-β-ketoacetates
摘要:
DMDO oxidation of functionalized alpha-diazo-beta-ketoacetates, formed by zinc triflate catalyzed Mukaiyama-aldol condensation of methyl diazoacetoacetate with aldehydes, occurred in quantitative yield to form dihydrofuranols that undergo acid catalyzed dehydration under mild conditions to generate 3-methoxy-furan-2-carboxylates in good yield. (C) 2011 Elsevier Ltd. All rights reserved.
Construction of Highly Functionalized Diazoacetoacetates via Catalytic Mukaiyama−Michael Reactions
摘要:
Functionalized diazo acelloacetates are prepared by an efficient Mukaiyama-Michael reaction between methyl 3-(trialkylsilanoxy)-2-diazo-3-butenoate and alpha,beta-unsaturated enones. Vinyl ether and ketone derivatives are both accessible in good to excellent yield through this methodology. The mild Lewis acid zinc(II) triflate is the optimal catalyst, and its loading can be as low as 0.1 mol %. In addition, zinc triflate was also found to be a superior catalyst for the related Mukaiyama-aldol reaction.