(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• oxirane [14]. A related study has demonstrated that (E)-butene 1a reacts with potassium persulfate to form 4,5-bistrifluoromethyl)-1,3,2-dioxathiolane 2,2-dioxide [15]. In 2021 Petrov published an article on the interaction of fluorinated olefins with fluorinated thioketones. In this publication it was

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• ][52][53][54][55][56][57][58] (Scheme 9). Thioketones, thiochalcones, and tertiary thioamides react as C=S super dipolarophilic agents. Jasiński et al. reported that these thiocarbonyl compounds react with trifluoromethylated hydrazonoyl halides to give trifluoromethylated 1,3,4-thiadiazoles via

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• THF switched the product to thioketone 99 (Scheme 14). Refluxing the thioketones 99 again with phenylhydrazine hydrochloride in ethanol resulted in the desired bis(indol-3-yl)sulfides 98. On the other hand, the treatment of thioketones 99 with phenylhydrazine afforded the corresponding hydrazones 100

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• thioketones reacted with donor–acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf)3 yielding tetrahydrothiophene derivatives, products of formal [3 + 2]-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2

• -arylcyclopropane dicarboxylates reacted with the corresponding aryl ferrocenyl thioketones in a completely diastereoselective manner to form single products in which (C-2)-Ar and (C-5)-ferrocenyl groups were oriented in a cis-fashion. In contrast, the same cyclopropanes underwent reaction with alkyl ferrocenyl

• thioketones to form nearly equal amounts of both diastereoisomeric tetrahydrothiophenes. A low selectivity was also observed in the reaction of a 2-phthalimide-derived cyclopropane with ferrocenyl phenyl thioketone. Keywords: [3 + 2]-cycloaddition reactions; donor–acceptor cyclopropanes; ferrocenyl

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• -aromatization of the imidazole ring. The same mechanism governs sulfur-transfer reactions with cycloaliphatic thioketones yielding the corresponding imidazole-2-thiones [13]. The isomerization of N-oxides 1 into the corresponding imidazol-2-ones can be easily performed by treatment with acetic anhydride at room

First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones

• Grzegorz Mlostoń,
• Katarzyna Urbaniak,
• Paweł Urbaniak,
• Anna Marko,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156

• –Alder reactions are rarely reported. However, aryl and hetaryl thioketones are known to react as ‘superdienophiles’, thereby yielding the corresponding 3,6-dihydro-2H-thiopyrans [11][12][13][14]. Despite the fact that thiochalcones exist in solution as mixtures of dimers [15][16], they enter into

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• intermediates in the synthesis of pharmaceuticals and various chemical entities such as allylic alcohols, benzoxathiepines, benzotiazepines, α-thioketones, α-substituted α,β-unsaturated enones, and β-hydroxysulfoxides [15]. Accordingly, a number of methodologies have been reported for their synthesis

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

• Grzegorz Mlostoń,
• Paulina Pipiak,
• Róża Hamera-Fałdyga and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 1900–1906, doi:10.3762/bjoc.13.185

• Trimethylsilyldiazomethane (TMS-CHN2) reacts readily with hetaryl thioketones to give sterically crowded 2-trimethylsilyl-4,4,5,5-tetrahetaryl-1,3-dithiolanes with complete regioselectivity at −75 °C as well as at rt. Thiofluorenone, a relatively stable and highly reactive aryl thioketone, yields upon treatment with TMS

• -CHN2 at −60 °C the corresponding 1,3,4-thiadiazoline. This unstable cycloadduct undergoes decomposition at ca. −45 °C and the silylated thiocarbonyl S-methanide generated thereby is trapped with complete regioselectivity by aryl or hetaryl thioketones forming also sterically crowded 2-trimethylsilyl

• presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents. Keywords: diazomethanes; 1,3-dipolar cycloadditions; olefination reactions; reaction mechanisms; thioketones; Introduction Aryl and hetaryl-substituted

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• intermediate, delocalized diradical species. The influence of selenium as a ‘heavy atom’ for stabilization of this intermediate has been emphasized. Keywords: 1,3-dipolar cycloadditions; reaction mechanisms; reactive intermediates; thiocarbonyl S-methanides; thioketones; Introduction Thiocarbonyl S

• pathway was excluded. Results and Discussion In a recent publication, reactions of hetaryl phenyl and dihetaryl thioketones with diazomethane have been described, and the formation of 1,3-dithiolanes as well as unexpected, hitherto unknown, dimers of the intermediate thiocarbonyl S-methanide was observed

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• Ferrocenyl hetaryl thioketones react smoothly with in situ generated thiocarbonyl S-methanides to give 1,3-dithiolanes. In the case of aromatic S-methanides, the sterically more crowded 4,4,5,5-tetrasubstituted 1,3-dithiolanes (2-CH2 isomers) were formed as sole products. The reactions with cycloaliphatic S

• ; ferrocene; thiocarbonyl S-methanides; thioketones; Introduction In a recent publication, a straightforward method for the synthesis of hitherto little known ferrocenyl aryl/hetaryl thioketones of type 1 via a standard procedure by treatment of the corresponding ferrocenyl ketones with Lawesson reagent was

• thioketones are remarkably stable in comparison with their aromatic analogues. Thus, the convenient access to thioketones 1 permitted their exploration for the synthesis of diverse sulfur heterocycles based on the reactivity of compounds containing a C=S group, known as ‘superdipolarophiles’ [2] or

Diradical reaction mechanisms in [3 + 2]-cycloadditions of hetaryl thioketones with alkyl- or trimethylsilyl-substituted diazomethanes

• Grzegorz Mlostoń,
• Paulina Pipiak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 716–724, doi:10.3762/bjoc.12.71

• dihetaryl and aryl/hetaryl thioketones with 2-diazopropane, diazoethane, and (trimethylsilyl)diazomethane were studied at variable temperature. The experiments showed that reactions with 2-diazopropane carried out at –75 °C occur mainly via the initially formed, relatively stable 1,3,4-thiadiazolines as

• spontaneous desulfurization, are the main products. In contrast, reactions with diazoethane occurred predominantly via initially formed diradicals, which in cascade processes gave sterically crowded 4,4,5,5-tetrahetaryl-1,3-dithiolanes as major products. Finally, the reaction of dihetaryl thioketones with

• . Remarkably, in no single case, the ‘head-to-head dimerization’ of aryl/hetaryl and dihetaryl substituted thiocarbonyl ylides was observed. Keywords: [3 + 2]-cycloadditions; diazoalkanes; diradicals; 1,3-dithiolanes; reaction mechanisms; thioketones; Introduction Cycloaddition reactions belong to the most

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

• Grzegorz Mlostoń,
• Paulina Grzelak,
• Maciej Mikina,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2015, 11, 576–582, doi:10.3762/bjoc.11.63

• , University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland 10.3762/bjoc.11.63 Abstract Selected hetaryl and aryl thioketones react with acetylenecarboxylates under thermal conditions in the presence of LiClO4 or, alternatively, under high-pressure conditions (5 kbar) at room temperature

• sulfones. Keywords: dimethyl acetylenedicarboxylate (DMAD); hetero-Diels–Alder reactions; high pressure reactions; methyl propiolate; thioketones; thiopyrans; Introduction A series of recent publications evidence that, in contrast to earlier opinions, thioketones are useful building blocks for the

• preparation of diverse sulfur heterocycles [1][2][3]. Studies performed by Huisgen and coworkers are of special importance and they resulted in the formulation of the name ‘superdipolarophiles’ for aromatic thioketones [4][5][6]. In addition, Sauer and coworkers called them ‘superdienophiles’ based on kinetic

On the strong difference in reactivity of acyclic and cyclic diazodiketones with thioketones: experimental results and quantum-chemical interpretation

• Andrey S. Mereshchenko,
• Alexey V. Ivanov,
• Viktor I. Baranovskii,
• Grzegorz Mloston,
• Ludmila L. Rodina and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2015, 11, 504–513, doi:10.3762/bjoc.11.57

• , Poland 10.3762/bjoc.11.57 Abstract The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,E-conformers and leads to the formation of transient thiocarbonyl ylides in two stages. The thermodynamically favorable further transformation of C

• stage of the cycloaddition process. Keywords: diazocarbonyl compounds; 1,3-dipolar cycloaddition; 1,3-oxathioles; thiiranes; thiocarbonyl ylides; thioketones; Introduction Dipolar cycloadditions of diazo compounds have been of great interest for a long time as they provide a means for the preparation

• performed a detailed experimental study of reactions of a series of 2-diazo-1,3-dicarbonyl compounds 1 with aromatic and aliphatic thioketones 2, and it was established that they occurred in a varied manner: acyclic diazodicarbonyl compounds 1 readily reacted with thioketones 2, whereas carbocyclic

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• react at room temperature with cycloaliphatic thioketones, e.g. 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one and adamantanethione, via a cascade process in which the key step is a 1,5-electrocyclization of the intermediate thiocarbonyl ylide leading to tetrasubstituted spirocyclic 1,3-oxathioles. The

• -oxathiole to alkene were performed at the DFT PBE1PBE/6-31G(d) level. Keywords: 1,3-dipolar electrocyclization; 1,5-dipolar electrocyclization; 1,3-oxathioles; thiocarbonyl ylides; thiiranes; thioketones; Introduction Aryl- and alkylsubstituted thioketones exhibit high 1,3-dipolar reactivity towards

• diazoalkanes, diazoesters and diazoketones [1][2][3][4]. Due to their high dipolarophilic reactivity thioketones were given the name ‘superdipolarophiles’ [3][4]. It might be expected that these highly reactive dipolarophiles could also easily react with the deactivated 1,3-dipoles of 2-diazo-1,3-dicarbonyl

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• thioketones 20–22 may be due to electronic effects and prevention of the formation of certain tautomers by the C4-methyl groups in compounds 13–15 [22]. To investigate the influence of the C4-methyl groups on the regioselective thionation reaction, we treated unsubstituted 5,5-dimethylhydantoin 6 with

Asymmetric synthesis of tertiary thiols and thioethers

• Jonathan Clayden and
• Paul MacLellan

Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68

• simple tertiary alcohols is generally achieved by controlling enantiofacial selectivity in nucleophilic attack on a prochiral ketone [10], comparable approaches to tertiary thiols 1 are not practical due to the instability of thioketones, their tendency to undergo nucleophilic attack at sulfur rather