Hetaryl Thioketones: Synthesis and Selected Reactions

Abstract

A series of phenyl/hetaryl and bishetaryl thioketones have been prepared via oxygen/sulfur exchange of the corresponding ketones by treatment with Lawesson's reagent. The nonsymmetrical ketones were conveniently accessible via the reactions of lithiated furan, thiophene, and selenophene with N,N-dimethylbenzamide and hetarylcarboxamides, respectively, whereas the symmetrical ketones were obtained by treatment of ethyl N,N-dimethylcarbamate with 2 equiv of lithiated heterocycles. Under typical conditions, selected examples of the hetaryl thioketones were oxidized selectively to give thiocarbonyl S-oxides (sulfines). Reactions with diazomethane at -65°C yielded 1,3-dithiolanes in a regioselective manner and hetero-Diels-Alder reactions of 2-thienyl substituted thioketones with dimethyl acetylenedicarboxylate yielded the corresponding 7H-thieno [2,3-c]

Selenophen‐2‐yl‐Substituted Thiocarbonyl Ylides – at the Borderline of Dipolar and Biradical Reactivity

“…1:1 mixture of isomeric 1,3-dithiolanes of type 9 exclusively [13]. This observation suggests that the presence of a selenophen-2-yl substituent is a necessary condition for the formation of the dimer of type 10.…”

“…On the other hand, the same reaction with 8b and 8c bearing electron-donating substituents gave predominantly mixtures of isomeric 1,3-dithiolanes 9b and 9c, respectively, and only traces of the dimers 10 were detected. Finally, the reaction with the symmetric di(selenophen-2-yl) thioketone (8g) led to 1,3-dithiolanes as the major products [13], but traces of the unstable dimer 10g could also be identified in the crude mixture. …”

Conformers of diheteroaryl ketones and thioketones: a quantum chemical study of their properties and fundamental intramolecular energetic effects

“…We focus on formaldehyde and thioformaldehyde disubstituted with such a fivemembered heteroaryl group as 2-furanyl, 2-thiophenyl, 2-selenophenyl, 2-pyrrolyl or 1-methyl-2-pyrrolyl. Part of the compounds considered here have been synthesized only recently [9]. The structure of the investigated diheteroaryl ketones 1a-5a is sketched in Scheme 1.…”

Reduction of Thiocarbonyl Compounds with Lithium Diisopropylamide

“…1.25 equivalents of LDA and subsequent treatment of the initial product with MeI led to the corresponding methylsulfides 11c [20] and 11d, respectively, which were isolated in 52 and 41% yield (Scheme 4). On the other hand, the analogous reaction of the hetarylthioketones phenyl(2-thienyl)methanethione (10e) [21] and di(selenophen-2-yl)methanethione [22] led to complex mixtures of diverse products, and only in the case of 10e, the corresponding methylsulfide 11e was obtained in very low yield (9%). Finally, the reduction of diferrocenylthioketone (10f) was performed successfully by using 3.2 equivalents of LDA and 6.5 equivalents of MeI.…”