title: Efficient One-Pot Synthesis of Dithieno(dibenzothieno)-Fused Cycloheptanones, Tropones, and Cyclooctanones.
abstract: The reactions of alpha,beta-unsaturated amide/triflic anhydride complexes (generated in situ from the corresponding amides and triflic anhydride) with dithiophenes and dithienylmethanes proceed as tandem alkylation-Vilsmeier-Haack acylation to form dithieno- and dibenzothieno-fused cycloheptanones and cyclooctanones in moderate to good yields. The reactions of 2-bromo-N,N-dimethylacrylamide/triflic anhydride complex allow preparation of tropones in a simple one-pot procedure. The reaction of 2,2-dibenzothienylmethane with dimethylacrylamide/triflic anhydride complex proceeds unusually to afford dimethylaminonaphthalene in addition to the predictable fused cyclooctanone.
authors.affiliation: Department of Chemistry, Moscow State University, Moscow 119899, Russia.
authors.forename: Valentine G.
authors.initials: VG
authors.lastname: Nenajdenko
authors.forename: Ivan L.
authors.initials: IL
authors.lastname: Baraznenok
authors.forename: Elizabeth S.
authors.initials: ES
authors.lastname: Balenkova