A novel P(NMe2)3-mediated reductive [1+4] annulation reaction between isatins and enones has been developed, providing the facile synthesis of spirooxindole-dihydrofurans. This reaction unveils the first practical approach to construct five-membered cyclic motifs via a Kukhtin-Ramirez adduct involved [1+4] annulation mode.

The preparation of trans-dihydrofurans has been achieved by a one-pot condensation reaction of 4-bromophenacyl bromide, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione using biosynthesized CuO nanoparticles under reflux conditions in ethanol. CuO nanoparticles (CuO NPs) were prepared using extractof leaves of Ajuga chamaecistus Subsp. Scoparia. The key advant...

The preparation of trans-dihydrofurans has been achieved by a one-pot condensation reaction of 4-bromophenacyl bromide, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione using biosynthesized CuO nanoparticles under reflux conditions in ethanol. CuO nanoparticles (CuO NPs) were prepared using extractof leaves of Ajuga chamaecistus Subsp. Scoparia. The key advant...

In this work an efficient one-pot synthesis of substituted pyrroles 7a-n is described, which involves the in situ formation of dihydrofurans ethyl 5-butoxy-2-methyl-4,5-dihydrofuran-3-carboxylate (4), 1-(5-butoxy-2-methyl-4,5-dihydrofuran-3-yl)ethanone (5) and 5-butoxy-4,5-dihydrofuran-3-carbaldehyde (6) followed by reaction with primary amines.

A DDQ-mediated domino reaction (up to six steps in a single process) has been developed to selectively provide substituted dihydrofurans from a common starting material containing a cyclic bis-thioenol ether. Study of the reaction mechanism highlighted a role played by the sulfur-containing moiety in influencing reaction rate and stereoselectivity.

A new type of TfOH-catalyzed tandem cyclopropane ring enlargement/C-C formation/etherification reaction between alkynylcyclopropanes and 1,3-diketones to cyclobutane-fused dihydrofurans is described. The reaction tolerates a range of aryl and alkyl substituents with moderate to good yields.

Typical transition metal-catalyzed oxycyclization of allenols takes place at the terminal allene carbon via a 5-endo path and forms dihydrofurans. A copper-catalyzed protocol brought about reversed regioselectivity, generating series trisubstituted epoxides through 3-exo-cyclization/sulfonylation cascade. The current stoichiometry control regioselectivity may open singular opportunities in chem...

An asymmetric gold(I)-catalyzed [3+2] cycloaddition of propargyl acetals/ketals and aldehydes is reported, which proceeds via stepwise migration-fragmentation of acetals/ketals and cycloaddition of the in situ generated gold-carbenoid intermediate. Various functionalized 2, 5-dihydrofurans were obtained in good yields and high enantioselectivities. Furthermore, an example of the first gold(I) c...

In the past two decades, alkene metathesis has risen in prominence to become a significant synthetic strategy for alkene formation. Many total syntheses of natural products have used this transformation. We review the use, from 2003 to 2015, of ring-closing alkene metathesis (RCM) for the generation of dihydrofurans or -pyrans in natural product synthesis. The strategies used to assemble the RC...