An Efficient and General Iron-Catalyzed One-Pot Synthesis of Furans via α-Hydroxy Ketones and Activated Alkynes

Copper-Catalyzed Regioselective Annulation of β-Keto Esters and Propargyl Acetates: Access to Polysubstituted Furans

A copper-catalyzed regioselective annulation reaction, conducted without ligands or oxidants, has been developed for the preparation of multisubstituted furans from the readily available starting materials, β-keto esters and propargyl acetates. This process accommodates a wide range of functional groups, resulting in furan skeletons with diverse substitution patterns. The method's potential synthetic utility is highlighted by its applicability in gram-scale preparations and late-stage modifications of natural products.

Silver(i)/base-promoted propargyl alcohol-controlled regio- or stereoselective synthesis of furan-3-carboxamides and (Z)-enaminones

A novel and facile regioselective synthesis of furan-3-carboxamides by a silver(i)/base-promoted reaction of propargyl alcohol with 3-oxo amides has been demonstrated. This one-pot protocol provides a rapid synthetic approach to diverse trisubstituted furan-3-carboxamides via cascade nucleophilic addition, intramolecular cyclization, elimination, and isomerization reactions. Employing a substituted propargyl alcohol, (Z)-enaminones have been obtained with high stereoselectivities by a Ag2CO3-promoted reaction starting from 3-oxo amides via C-N bond cleavage.

A co-operative effect of visible light photo-catalysis and CoFe2O4 nanoparticles for green synthesis of furans in water

A novel approach to poly-functionalized furan synthesis is disclosed via oxidative decarboxylative [3+2] cycloaddition using co-operative catalysis by visible light and CoFe₂O₄ nanoparticles.

Copper(I)/Ligand-Catalyzed 5-endo Radical Cyclization-Aromatization of 2,2,2-Trichloroethyl Vinyl Ethers: Synthesis of 2,3-Difunctionalized 4-Chlorofurans

Copper(I)/ligand-catalyzed one pot synthesis of highly substituted 2,3-difunctionalized-4-chlorofurans has been reported. The reaction proceeds via a Cu(I)-catalyzed regioselective 5-endo-trig radical cyclization of 2,2,2-trichloroethyl vinyl ethers followed by the base-promoted dehydrochlorination. The success of the kinetically disfavored 5-endo cyclization was attributed to the formation of captodatively stabilized radical intermediate in the cyclization step and relatively high reaction temperature. Synthetic application of this protocol was also demonstrated in the preparation of alkyl and aryl substituted 4-chlorofuranonapthoquinones.

Direct CuO nanoparticle-catalyzed synthesis of poly-substituted furans via oxidative C–H/C–H functionalization in aqueous medium

Here, we have reported CuO nanoparticles catalyzed synthesis of poly-functionalized furan derivatives via direct functionalization of α,β-unsaturated carbonyl compounds through conjugate addition initiated domino reactions in aqueous ethanol.

Synthesis of multisubstituted furans via Cu(i)-catalyzed annulation of ketones with alkynoate under ligand- and additive-free conditions

A simple and efficient Cu(i)-catalyzed strategy for synthesis of mutisubstituted furans has been developed and this ligand- and additive-free annulation method is well suitable for both nonactivated arylmethyl ketones 1,3-dicarbonyl compounds.