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Efficient syntheses of new 2,2′-disubstituted-2,3-dihydrofuran(5H)-4-one, spiro{benzofuran-2,2′-bicyclo[2.2.1]heptan}-4(5H)-one derivatives and natural polyketide analogues have been achieved via the oxidative [3 + 2] cycloaddition of 1,3-dicarbonyl compounds with monoterpenes myrcene, camphene and natural phenyl propenes namely anethole, safrole respectively. Interestingly, the reaction of isoprene and myrcene with 1,3-dicarbonyl compounds yielded 2,2-disubstituted tetrahydrobenzofuran-4(5H)-one derivatives at room temperature. Thus, several substituted 2,3-dihydrofuran derivatives (3a-3h) with potential biological activity have been synthesized.

In the presence of K2CO3, benzoylmethyltriphenylarsonium bromide 1 reacted with 3‐arylidene‐2,4‐pentadione 2 in benzene under heating to give 2‐benzoyl‐3‐aryl‐4‐acetyl‐5‐methyl‐trans‐2,3‐dihydrofurans 3 in good yield with high stereoselectivity.

Anhydrous zirconium tetrachloride is found to be an efficient catalyst for the Imino Diels–Alder reactions of N‐benzylideneanilines with 3,4‐dihydro‐2H‐pyran and 2,3‐dihydrofuran to afford pyrano and furo [3,2‐c] quinolines in good yields.

In the presence of K2CO3, acetylmethyltriphenylarsonium bromide 1 reacted with 3‐arylidene‐2,4‐pentadione 2 in benzene at 50°C for 48 h to give 2‐(Z‐4‐oxo‐2‐penten‐2‐yl)‐3‐substitutedphenyl‐4‐acetyl‐5‐methyl‐trans‐2,3‐dihydrofurans 3 in good yield with high stereoselectivity.

N2-Acetyl-8-bromoguanine has been found to react readily with 2,3-dihydrofuran in DMF in the presence of acid catalyst at room temperature to give 9-(tetrahydrofuryl-2)-8-bromo-N2-acetylguanine in high yield. The structures of this compound and its deacetylated derivative were assigned by H and C NMR spectroscopy.

The palladium-catalyzed arylation and vinylation of 2,3-dihydrofuran with aryl and alkenyl iodonium salts afforded 2-phenyl- or 2-alkenyl-2,5-dihydrofurans at room temperature in an aqueous medium.

A formal synthesis of (2R-cis)-4-methyl-1-(2,3,4,5-tetrahydro-5-methyl-[2,3′-bifuran]-2-pentanone, or ipomeamarone (1) [494-23-5] was accomplished from 3-furaldehyde 5 and ethyl-2-bromocrotonate 4. The key step involved the formation of the dihydrofuran ring in 2 via a vinyloxirane rearrangement of 3 in the [2+3] dihydrofuran annulation. Mechanistic duality of reactions of those tetrahydrofurans possessing acidic hydrogens adjacent to the ring is addressed.