Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent.
Functionalized methyl cis-4-oxoalk-2-enoates 2 are synthesized in a one-pot procedure by singlet oxygen oxygenation of the corresponding 2-methoxyfurans 1 in methanol and reduction of the resulting hydroperoxides 4 and 5 by the sulfides 6 which are selectively oxidized into the sulfoxides 7. The synthetic method has a wide range of applicability and affords compounds 2 stereoselectively and in good yields; concomitantly the sulfoxides 7 are obtained in excellent yields.
The first nucleophilic aromatic substitution of suitably activated 2-methoxyfurans with Grignard reagents
作者:M.Rosaria Iesce、M.Liliana Graziano、Flavio Cermola、Stefania Montella、Lucrezia Di Gioia
DOI:10.1016/s0040-4039(03)01430-8
日期:2003.7
The reaction of 2-methoxyfuroates 1 with Grignardreagents 2 leads to tertiary alcohols or SNAr products depending on the position of the alkoxycarbonyl group. OMe-Displacement occurs only for 3-substituted derivatives. It takes place even for 3-acetyl-2-methoxyfuran while the presence of a further ester function at 4 position induces the formation of the sole 4-tertiary alcohol. The OMe-substitution
Catalyst-Controlled Ring-Opening Cycloisomerization Reactions of Cyclopropenyl Carboxylates for Highly Regioselective Synthesis of Different 2-Alkoxyfurans
作者:Jie Chen、Shengming Ma
DOI:10.1002/asia.201000324
日期:2010.11.2
Differently substituted 2‐alkoxyfurans (2,3,4‐ or 2,3,5‐trisubstituted furans) were highlyregioselectively synthesized by means of the ring‐opening cycloisomerization of the same cyclopropenylcarboxylates with good yields in different solvents and excellent regioselectivity by using [Cu(acac)2] (acac=acetylacetonate) or [RuCl2(PPh3)3] as the catalyst, respectively. The structures of these two different