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Three-component condensation of in situ generated pyridinium aroylmethylides with isatins or aromatic aldehydes and cyclic 1,3-dicarbonyl compounds gave a series of condensed 2-aroyl-2,3-dihydrofurans. The reaction proceeds diastereoselectively and represents a cascade process involving the Knoevenagel condensation, the carbo-Michael reaction, and intramolecular nucleophilic substitution. The possibility of reductive rearrangement of spirocyclic furanyl-substituted oxindole into a pyran derivative by the action of zinc in acetic acid was shown.

Three-component condensation of in situ generated pyridinium acyl methylides with aromatic aldehydes and 4-hydroxythiocoumarin led to a series of 2-acyl-2,3-dihydro-4H-thiochromeno[4,3-b]furan-4-ones. The reaction proceeds diastereoselectively with the formation of trans-isomers and represents a cascade process involving the Knoevenagel condensation, carbo-Michael reaction, and intramolecular nucleophilic substitution. The subsequent redox rearrangement of 2-acyl-2,3-dihydro-4H-thiochromeno[4,3-b]furan-4-ones by the action of Zn and ZrCl4 grants access to 4H,5H-thiochromeno[4,3-b]pyran-5-ones.

The addition of dihalocarbenes to 1H-benzo[f]chromenes and 4H-chromenes gave a number of dihalotetrahydro(benzo)cyclopropa[b]-chromenes containing donor and acceptor substituents at different positions. It was found that in the case of 1,3-disubstituted 1H-benzo[f]-chromenes, the reaction proceeds diastereoselectively with the formation of trans-isomers. 12H,13H-7a,12a-Methanobenzo[f]indeno-[1,2-b]chromene and 12,13-dihydro-14H-7a,13a-methanodibenzo[a,h]xanthene, representatives of new heterocyclic systems, were obtained.

By the reaction of 3-aryl-1H-benzo[f]chromenes with N-bromosuccinimide in aqueous acetone, a series of 2-aroyl-1,2-dihydronaphtho-[2,1-b]furans unsubstituted at the C-1 position were obtained as a result of formal addition of hypobromous acid to the pyran fragment and intramolecular nucleophilic substitution. This reaction is a rare example of the ring constriction in 1H-benzo[f]chromene series.

The oxidation of 3-aryl-1H-benzo[f]chromenes with Koser’s reagent in methanol afforded a series of benzoflavylium tosylates. This reaction is the first example of the use of polyvalent iodine compounds to access arene-condensed pyrylium salts.

The reaction of 1,1-bis(morpholino)ethene with precursors of о-quinone methides derived from Mannich bases of phenols and 2-naphthols provided a series of chromeno[2,3-b]chromenes. The cascade process included a hetero-Diels–Alder reaction between о-quinone methide and ketenaminal, elimination of secondary amine, and [4+2] cycloaddition between о-quinone methide and the chromene intermediate.

A new method is proposed for the preparation of 2-aroylbenzofurans and 2-aroylnaphtho[2,1-b]furans via oxidative rearrangement of 2,4-diaryl-4Н-chromenes and 1,3-diaryl-1Н-benzo[f]chromenes in the presence of selenium dioxide.