The triphenylphosphine-catalyzed formal [3 + 2] cycloaddition of allenoates and trifluoromethylketones was realized to give the corresponding dihydrofurans in good yields with excellent γ-regioselectivities. Hydrogenation of the dihydrofurans gave 2,4,4-trisubstituted tetrahydrofurans in good yields with exclusive cis-selectivities.

A convenient microwave irradiation protocol was utilized for the synthesis of b-ketosulfones 1-5 in good yields. These sulfones reacted with alkenes through a radical oxidative cyclization mediated by Mn(OAc)3. Dihydrofurans 6-10 were obtained in moderate to good yields starting from 1,1-disubstituted alkenes. Dihydrofurans 11-15 were synthesized in moderate yields and unexpected cyclopropanes ...

An efficient one-pot method for the enzyme- and ruthenium-catalyzed enantioselective transformation of α-allenic alcohols into 2,3-dihydrofurans has been developed. The method involves an enzymatic kinetic resolution and a subsequent ruthenium-catalyzed cycloisomerization, which provides 2,3-dihydrofurans with excellent enantioselectivity (up to >99 % ee). A ruthenium carbene species was propos...

A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.

The asymmetric synthesis of gamma-azido trans-cyclopropyl ketones is accomplished via a short, simple and efficient sequence. The cyclopropanation step is achieved by an intramolecular nucleophilic ring closure, with a diphenylphosphinate leaving group, to give trans-cyclopropane exclusively. beta-Keto-diphenylphosphine oxides cyclise to form optically active dihydrofurans. All possible diaster...

A straightforward, efficient, and reliable approach to synthetically valuable 2,3-dihydrofurans via a reaction between Corey ylide and α,β-unsaturated ketones has been developed. The use of simple and widely spread starting materials as well as mild reaction conditions and scalability provide a broad scope of 2,3-dihydrofurans.

An efficient and simple approach has been developed for the regio-selective synthesis of iodo-substituted dihydrofurans from amine substituted alkynols. The resulting iodo-substituted dihydrofurans have been further diversified by C-C couplings and C-N coupling reactions to afford a diverse range of substituted dihydrofuran derivatives.

Phosphorylated α-hydroxyallenes 1 and 2 were smoothly converted into the corresponding 2,5-dihydrofurans 3 and 4 in an 5-endo-trig cycloisomerization reaction by using 5 mol % of coinage metal salts as catalyst. Experimental conditions such as the type of the solvent, the reaction temperature, the mol % and the type of the catalyst were optimized. This mild and efficient cyclization method can ...

There is growing awareness that heterogeneous reactions may be important in the atmospheric formation of secondary organic aerosols (SOA). Here, we report on the investigation of a series of recently identified heterogeneous reactions that convert 1,4-hydroxycarbonyls, a major product of alkane oxidation, to cyclic hemiacetals and then dihydrofurans in the particle-phase. Through these reaction...

The palladium-catalyzed reaction of (hetero)aryl bromides, chlorides, and nonaflates with α-allyl-β-ketoesters provides ready efficient access to functionalized 2,3-dihydrofurans. The reaction tolerates several useful substituents including chloro, fluoro, ether, ketone, ester, cyano, and nitro groups.