Synthesis of 2,4-disubstituted furans and 4,6-diaryl-substituted 2,3-benzo-1,3a,6a-triazapentalenes

Abstract

Reactions of acylacetylenes 1a-h with benzotriazole 2 give intermediates 3a-h. The treatment of 3a-h with trimethylsulfonium iodide in the presence of base give intermediate oxiranes 4a-h and 2,3-benzo-1,3a,6a-triazapentalenes 7d-g depending on substituent. Acid-catalyzed rearrangement of crude 4a-h give 2,4-disubstituted furans 5a-h.