A general approach is described for the formation of tetrahydrothiepines using donor-acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewis acid catalyzed formal (4 + 3)-cycloaddition reaction with cyclopropanes three-atom blocks. Under mild conditions various synthesized good yields stereospecific high functional group tolerance.

A general approach for preparation of two types polyfunctionalized 3-trifluoromethylpyrazoles is reported. The protocol comprises (3 + 2)-cycloaddition the in situ generated trifluoroacetonitrile imines with enones leading to trans-configured 5-acyl-pyrazolines a fully regio- and diastereoselective manner. Initially formed cycloadducts were aromatized by treatment manganese dioxide. Depending on solvent used, oxidation step either led substituted pyrazoles (DMSO) or proceeded via deacylative...

Previously difficult to prepare, aliphatic and alicyclic trifluoromethylketones (e.g. 1 2), which are of pharmacalogic interest as potential enzyme inhibitors, can now be synthesized easily efficiently. The one-step reaction starting with carbonic esters trimethyl(trifluoromethyl)silane is induced by tetrabutylammonium fluoride in nonpolar, aprotic solvents proceeds without formation double-addition products.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe first two-step 1,3-dipolar cycloadditions: non-stereospecificityRolf. Huisgen, Grzegorz. Mloston, and Elke. LanghalsCite this: J. Am. Chem. Soc. 1986, 108, 20, 6401–6402Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/ja00280a053https://doi.org/10.1021/ja00280a053research-articleACS PublicationsRequest reuse permissionsArticle...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe first two-step 1,3-dipolar cycloadditions: interception of intermediateRolf Huisgen, Grzegorz Mloston, and Elke LanghalsCite this: J. Org. Chem. 1986, 51, 21, 4085–4087Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/jo00371a039https://doi.org/10.1021/jo00371a039research-articleACS PublicationsRequest reuse permissionsArticle...

Abstract The cycloaddition of diazoalkanes to CS double bonds furnishes 1,3,4‐thiadiazolines which give rise thiocarbonyl ylides and N 2 in a cycloreversion. Thiocarbonyl are nucleophilic 1,3‐dipoles interceptible by thiones or electron‐deficient alkenes alkynes as dipolarophiles affording 1,3‐dithiolanes, dihydrothiophenes thiolanes, respectively. In the absence reaction partners, undergo electrocyclization, dimerization, β‐H abstraction Wagner‐Meerwein rearrangement.

Abstract The reactions of aryl (selenophen‐2‐yl) thioketones with CH 2 N occur spontaneous elimination , even at low temperature (−65°), to give regioselectively sterically crowded 4,4,5,5‐tetrasubstituted 1,3‐dithiolanes and/or a novel type twelve‐membered dithia‐diselena heterocycles as dimers the transient thiocarbonyl S ‐methanides. ratio these products depends on substituent located C(4) phenyl ring. Whereas formation corresponds [3+2] cycloaddition an intermediate ylide starting...

The crystal and molecular structures of 3-methyl-2,4-diphenyl-(1,3)-thiazolidine-5-spiro-2'-adamantane 3-methyl-2,4,5,5-tetraphenyl-(1,3)-thiazolidine are investigated showing the existence C(sp2)−H···S C(sp2)−H···N intramolecular contacts. use Bader theory shows that C−H...S interactions existing in may be treated as weak H bonds. C−H...N also analyzed here for simple modeled complexes (1,3)-thiazolidine proton acceptor donators: HF, H2O, C2H4, C2H2 molecules. calculations these were...

Extremely rare: A CS triple bond can be assigned to HCSOH, a new molecule prepared from H2CSO by photochemical [1,3]H-shift. But does this formal description agree with analyses on the basis of IR vibrations, lengths, orders, molecular orbitals, and compliance constants? Molecules like challenge refine our current understanding chemical bonding. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or...

Abstract Analogues of the [2Fe‐2S] subcluster hydrogenase enzymes in which central group three‐atom chain linker between sulfur atoms is replaced by GeR 2 and SnR groups are studied. The six‐membered FeSCECS rings these complexes (E=Ge or Sn) adopt an unusual conformation with nearly co‐planar SCECS perpendicular to Fe‐Fe core. Computational modelling traces this result steric interaction Me axial carbonyls Fe (CO) 6 cluster low torsional strain for GeMe SnMe moieties owing long C−Ge C−Sn...

Abstract

The one-pot synthesis of 1,1,1-trifluoro- and 1,1-difluoro-2,2-diarylethanes from arenes fluorinated hemiacetals in the BF3–H2O system is described. reaction simple, clean, convenient, eliminating use organic solvents other expensive acid systems. economic, easy to prepare, offers ample acidity required for this reaction.

ABSTRACT A series of phenyl/hetaryl and bishetaryl thioketones have been prepared via oxygen/sulfur exchange the corresponding ketones by treatment with Lawesson's reagent. The nonsymmetrical were conveniently accessible reactions lithiated furan, thiophene, selenophene N , ‐dimethylbenzamide hetarylcarboxamides, respectively, whereas symmetrical obtained ethyl ‐dimethylcarbamate 2 equiv heterocycles. Under typical conditions, selected examples hetaryl oxidized selectively to give...

Fluorinated nitrile imines generated in situ from the corresponding fluoral-derived hydrazonoyl bromides smoothly react with monomeric aryl/hetaryl-substituted thiochalcones yielding 2,3-dihydro-1,3,4-thiadiazoles a chemo- and regioselective manner. The elaborated protocol can be efficiently applied starting precursors functionalized both electron-donating electron-withdrawing groups located at <i>para</i> position of aryl ring. In contrast, non-fluorinated do not enter (3+2)-cycloaddition...

Abstract Dihetaryl thioketones react with thiocarbonyl ylides to give 1,3‐dithiolanes in high yields. No competitive side reactions of the were observed, evidencing ‘superdipolarophilic’ character this less‐known group thioketones. Depending on type substituents present both ylide and thioketone, formal [3+2] cycloadditions occur complete regioselectivity or formation a mixture regioisomers. Regioselective sterically more crowded is explained via mechanism involving stabilized...

An efficient application of aryl and hetaryl thioketones as dienophiles in the enantioselective thia‐Diels–Alder reaction was explored for first time. It found that could serve useful heterodienophiles aminocatalytic, trienamine‐mediated [4+2] cycloadditions with 2,4‐dienals. This approach (up to 99:1 er ) efficiently promoted by diarylprolinol silyl ethers led new types potentially relevant 5,6‐dihydro‐2 H ‐thiopyrans.

GRAPHICAL ABSTRACTAryl, hetaryl, and ferrocenyl thioketones as versatile building blocks for exploration in the organic chemistry of sulfurAll authorsGrzegorz Mlostoń, Paulina Grzelak, Róża Hamera-Fałdyga, Marcin Jasiński, Pipiak, Katarzyna Urbaniak, Łukasz Albrecht, Joanna Hejmanowska & Heinz Heimgartnerhttps://doi.org/10.1080/10426507.2016.1252368Published online:28 October 2016

The superior ability of thiiranes (episulfides) to undergo ring-opening polymerization (ROP) in the presence anionic initiators allows preparation chemically stable polysulfide homopolymers. Incorporation elemental sulfur (S8) by copolymerization below floor temperature S8 permits placement a large quantity atoms mainchain. utility styrene sulfide (2-phenylthiirane; StS) for with is reported here. A few polysulfides differing depending on initial ratio StS and time were synthesized. Various...

The reactions of 1,4,5-trisubstituted imidazole 3-oxides 1a – k with cyclobutanethiones 5a,b in CHCl3 at room temperature give imidazole-2(3H)-thiones 9a high yield. second product formed this reaction is 2,2,4,4-tetramethylcyclobutane-1,3-dione (6a; Scheme 2). Similar occur 1 and adamantanethione (5c) as thiocarbonyl compound, well 1,2,4-triazole-4-oxide derivative 10 5a (Scheme 3). A mechanism by a two-step formation the formal cycloadduct type 7 via zwitterion 16 proposed 5. Spontaneous...

Reactions of dihetaryl and aryl/hetaryl thioketones with 2-diazopropane, diazoethane, (trimethylsilyl)diazomethane were studied at variable temperature. The experiments showed that reactions 2-diazopropane carried out –75 °C occur mainly via the initially formed, relatively stable 1,3,4-thiadiazolines as products [3 + 2]-cycloaddition diazo dipole onto C=S bond. latter decompose only higher temperature (ca. −40 °C) to generate thiocarbonyl S -isopropanide. In absence starting thioketone,...

Abstract The quantum‐chemical calculations of the thermal ring opening 1‐methyl‐2,3‐diphenyl‐ and 1,2,3‐triphenylaziridine with formation corresponding azomethine ylides S‐, U‐, W‐type as well their cycloaddition to dimethyl acetylenedicarboxylate (DMAD) 2,3‐dicyanobut‐2‐enedioate, were performed at DFT B3LYP/6‐31G(d) level theory PCM solvation model. are in complete accordance experimental results explain switch from concerted non‐concerted pathway depending on substituents dipolarophile...

GRAPHICAL ABSTRACTSynthesis of Ferrocenyl Thioketones and their Reactions with DiphenyldiazomethaneAll authorsGrzegorz Mlostoń, Róża Hamera & Heinz Heimgartnerhttps://doi.org/10.1080/10426507.2015.1071817Published online:10 December 2015

The 2-unsubstituted 1H-imidazole 3-oxides, considered as 'nitrone-like' azaheterocycles, are well known versatile building blocks, useful for the preparation of more complex systems containing an imidazole moiety. Their applications in diverse reactions, such isomerization to corresponding imidazol-2-ones, [3+2]-cycloadditions, sulfur transfer reactions leading imidazole-2-thiones, heterocyclizations fused heterocyclic systems, cross coupling discussed. New methods enantiomerically pure...