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Grzegorz Mloston - One of the best experts on this subject based on the ideXlab platform.
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a novel application of 2 silylated 1 3 Dithiolanes for the synthesis of aryl hetaryl substituted ethenes and dibenzofulvenes
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Grzegorz Mloston, Paulina Pipiak, Roza Hamerafaldyga, Heinz HeimgartnerAbstract: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-1,3-Dithiolanes. The obtained 1,3-Dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents.
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generation and reactions of thiocarbonyl s 2 2 2 trifluoroethanides synthesis of trifluoromethylated 1 3 Dithiolanes thiiranes and alkenes
Journal of Fluorine Chemistry, 2017Co-Authors: Marcin K Kowalski, Grzegorz Mloston, Emilia Obijalska, Heinz HeimgartnerAbstract:Abstract The ‘in situ’ generated 1,1,1-trifluorodiazoethane reacts with thioketones as C=S dipolarophiles in a two-phase system (DCM/H2O) at room temperature to yield trifluoromethylated 2,5-dihydro-1,3,4-thiadiazoles. Whereas stable crystalline products were obtained with cyclobutanethiones, the reaction with aromatic and heteroaromatic thioketones occured with spontaneous elimination of nitrogen. The formation of sterically crowded 4,4,5,5-tetrahetaryl-1,3-Dithiolanes indicates that thiocarbonyl S-methanides are formed immediately and entered formal [3+2]-cycloaddition as diradical species with the starting thioketone. A protocol for the preparation of 3,3,3-trifluoropropene derivatives starting from corresponding thioketones and 1,1,1-trifluorodiazoethane is also presented.
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A novel application of 2-silylated 1,3-Dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes
Beilstein-Institut, 2017Co-Authors: Grzegorz Mloston, Paulina Pipiak, Róża Hamera-fałdyga, Heinz HeimgartnerAbstract: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-1,3-Dithiolanes. The obtained 1,3-Dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents
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synthesis of ferrocenyl substituted 1 3 Dithiolanes via 3 2 cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl s methanides
Beilstein Journal of Organic Chemistry, 2016Co-Authors: Grzegorz Mloston, Anthony Linden, Roza Hamerafaldyga, Heinz HeimgartnerAbstract: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-methanides led to mixtures of 2-CH2 and 5-CH2 isomers with the major component being the sterically more crowded 2-CH2 isomers. The preferred formation of the latter products is explained by the assumption that the formal [3 + 2]-cycloadducts were formed via a stepwise reaction mechanism with a stabilized 1,5-diradical as a key intermediate. The complete change of the reaction mechanism toward the concerted [3 + 2]-cycloaddition was observed in the reaction of a sterically crowded cycloaliphatic thiocarbonyl ylide with ferrocenyl methyl thioketone.
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ferrocenyl substituted 1 3 Dithiolanes via 3 2 cycloadditions of thiocarbonyl s methanides with ferrocenyl hetaryl thioketones
Phosphorus Sulfur and Silicon and The Related Elements, 2016Co-Authors: Roza Hamera, Grzegorz MlostonAbstract:The aim of the present study was the investigation of the regioselectivity observed in the course of formation of 1,3-Dithiolaness via [3+2]-cycloaddition reactions of differently substituted thioc...
Heinz Heimgartner - One of the best experts on this subject based on the ideXlab platform.
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a novel application of 2 silylated 1 3 Dithiolanes for the synthesis of aryl hetaryl substituted ethenes and dibenzofulvenes
Beilstein Journal of Organic Chemistry, 2017Co-Authors: Grzegorz Mloston, Paulina Pipiak, Roza Hamerafaldyga, Heinz HeimgartnerAbstract: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-1,3-Dithiolanes. The obtained 1,3-Dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents.
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generation and reactions of thiocarbonyl s 2 2 2 trifluoroethanides synthesis of trifluoromethylated 1 3 Dithiolanes thiiranes and alkenes
Journal of Fluorine Chemistry, 2017Co-Authors: Marcin K Kowalski, Grzegorz Mloston, Emilia Obijalska, Heinz HeimgartnerAbstract:Abstract The ‘in situ’ generated 1,1,1-trifluorodiazoethane reacts with thioketones as C=S dipolarophiles in a two-phase system (DCM/H2O) at room temperature to yield trifluoromethylated 2,5-dihydro-1,3,4-thiadiazoles. Whereas stable crystalline products were obtained with cyclobutanethiones, the reaction with aromatic and heteroaromatic thioketones occured with spontaneous elimination of nitrogen. The formation of sterically crowded 4,4,5,5-tetrahetaryl-1,3-Dithiolanes indicates that thiocarbonyl S-methanides are formed immediately and entered formal [3+2]-cycloaddition as diradical species with the starting thioketone. A protocol for the preparation of 3,3,3-trifluoropropene derivatives starting from corresponding thioketones and 1,1,1-trifluorodiazoethane is also presented.
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A novel application of 2-silylated 1,3-Dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes
Beilstein-Institut, 2017Co-Authors: Grzegorz Mloston, Paulina Pipiak, Róża Hamera-fałdyga, Heinz HeimgartnerAbstract: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-1,3-Dithiolanes. The obtained 1,3-Dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents
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synthesis of ferrocenyl substituted 1 3 Dithiolanes via 3 2 cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl s methanides
Beilstein Journal of Organic Chemistry, 2016Co-Authors: Grzegorz Mloston, Anthony Linden, Roza Hamerafaldyga, Heinz HeimgartnerAbstract: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-methanides led to mixtures of 2-CH2 and 5-CH2 isomers with the major component being the sterically more crowded 2-CH2 isomers. The preferred formation of the latter products is explained by the assumption that the formal [3 + 2]-cycloadducts were formed via a stepwise reaction mechanism with a stabilized 1,5-diradical as a key intermediate. The complete change of the reaction mechanism toward the concerted [3 + 2]-cycloaddition was observed in the reaction of a sterically crowded cycloaliphatic thiocarbonyl ylide with ferrocenyl methyl thioketone.
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1 3 oxathiole and thiirane derivatives from the reactions of azibenzil and α diazo amides with thiocarbonyl compounds
Helvetica Chimica Acta, 1998Co-Authors: Martin Kagi, Grzegorz Mloston, Anthony Linden, Heinz HeimgartnerAbstract:The reactions of alpha-diazoketones la,b with 9H-fluorene-9-thione (2f) in THF at room temperature yielded the symmetrical l,3-Dithiolanes 7a,b, whereas lb and 2,2,4,4-tetramethylcyclobutane-1,3-dithione (2d) in THF at 60' led to a mixture of two stereoisomeric 1,3-oxathiole derivatives cis- and trans-9a (Scheme 2). With 2-diazo-1,2-diphenylethanone (lc), thioketones 2a-d as well as 1,3-thiazole-5(4H)-thione 2g reacted to give 1,3-oxathiole derivatives exclusively (Schemes 3 and 4). As the reactions with lc were more sluggish than those with la,b, they were catalyzed either by the addition of LiCIO4, or by Rh2(OAc)4. In the case of 2d in THF/LiCIO4 at room temperature, a mixture of the monoadduct 4d and the stereoisomeric bis-adducts cis- and trans-9b was formed. Monoadduct 4d could be transformed to cis- and rrans-9b by treatment with lc in the presence of Rh2(OAc)4 (Scheme 4). Xanthione (2e) and lc in THF at room temperature reacted only when catalyzed with Rh2(OAc)4, and, in contrast to the previous reactions, the benzoyl-substituted thiirane derivative 5a was the sole product (Scheme 4). Both types of reaction were observed with alpha-diazo amides ld,e (Schemes 5-7). It is worth mentioning that formation of I,3-oxathiole or thiirane is not only dependent on the type of the carbonyl compound 2 but also on the alpha-diazo amide. In the case of Id and thioxocyclobutanone 2c in THF at room temperature, the primary cycloadduct 12 was the main product. Heating the mixture to 60", 1,3-oxathiole 10d as well as the spirocyclic thiirane-carboxamide11lb were formed. Thiirane-carboxamides 11d - g were desulfurized with (Me2N)3P in THF at 60", yielding the corresponding acrylamide derivatives (Scheme 7). All reactions are rationalized by a mecha- nism via initial formation of acyl-substituted thiocarbonyl ylides which undergo either a 1,5-dipolar electrocyclization to give 1,3-oxathiole derivatives or a I,3-dipolar electrocyclization to yield thiiranes. Only in the case of the most reactive 9H-fluorene-9-thione (2f) is the thiocarbonyl ylide trapped by a second molecule of 2f to give I,3-dithiolane derivatives by a 1,3-dipolar cycloaddition.
Wenjing Xiao - One of the best experts on this subject based on the ideXlab platform.
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oxidative cross esterification of Dithiolanes with alcohols through a cross dehydrogenative coupling cdc deprotection sequence
ChemInform, 2012Co-Authors: Changjiang Yao, Ningjie Chang, Jiarong Chen, Wenjing XiaoAbstract:The one-pot cross-dehydrogenative coupling—deprotection of Dithiolanes with primary and secondary alcohols proceeds smoothly in the presence of CuI as catalyst to give the corresponding carboxylic esters in high yields.
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oxidative cross esterification of Dithiolanes with alcohols through a cross dehydrogenative coupling cdc deprotection sequence
Organic and Biomolecular Chemistry, 2012Co-Authors: Changjiang Yao, Ningjie Chang, Jiarong Chen, Wenjing XiaoAbstract:An unprecedented oxidative cross-esterification in an equimolar mixture of Dithiolanes, alcohols and water through a CDC/deprotection sequence has been developed. The reaction itself features simple experimental procedures under very mild conditions and offers a new strategic protocol for the direct and efficient synthesis of structurally diverse esters.
Viacheslav A. Petrov - One of the best experts on this subject based on the ideXlab platform.
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thiophilic ring opening reactions of 3 3 bis trifluoromethyl 5 alkoxy 1 2 Dithiolanes under action of nucleophiles
Journal of Fluorine Chemistry, 2018Co-Authors: Viacheslav A. PetrovAbstract:Abstract The reaction of 3,3-bis(trifluoromethyl)-5-alkoxy-1,2-Dithiolanes (RO= OEt or OBu-n) proceeds through thiophilic attack of BuLi leading to the formation of ring-opened product BuSCH(OR)CH2C(CF3)2SLi, which can be converted into the corresponding thiols or sulfides by the reaction with H+ or alkyl halide. Interaction of 3,3-bis(trifluoromethyl)-5-n-butoxy-1,2-dithiolane with CF3Si(CH3)3 resulted in unusual reaction leading to the formation of CF3SCH(OBu)CH2C(CF3)=CF2 (7). The treatment of 7 with CsF in the presence pentafluoropyridine led to equimolar mixture of 2-n-butoxy-1,1-bis(trifluoromethyl)cyclopropane and 4-(trifluoromethylthio)tetrafluoropyridine (as a result of interception of liberated in this process CF3S- anion by pentafluoropyridine).
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Remarkable effect of metal fluoride catalyst on reaction of hexafluoropropene, sulfur and vinyl ethers. Convenient synthesis of 2,2-bis(trifluoromethyl)-4-R-thietanes, 3,3-bis(trifluoromethyl)-5-R-1,2-Dithiolanes and 2,2-bis(trifluoromethyl)-4-R-1,3-
Journal of Fluorine Chemistry, 2010Co-Authors: Viacheslav A. Petrov, Will MarshallAbstract:Abstract It was demonstrated that the outcome of the reaction of hexafluoropropene, sulfur and vinyl ether strongly depends on the catalyst and reaction conditions. The reaction of HFP and Sx leading to the formation of 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietane (1) when it is catalyzed by CsF, proceeds under milder conditions and is easier to control compared to KF catalyzed process. The order of addition of reagents plays a crucial role on the outcome of the reaction. For example, the addition of vinyl ether to pregenerated solution of 1 in DMF solvent results in slow reaction, leading to the corresponding 2,2-bis(trifluoromethyl)-4-R-thietanes in 8–91% yield, and it is catalyzed by either by KF or CsF. The addition of second mole of sulfur to the solution of 2,2-bis(trifluoromethyl)-4-R-thietanes in the presence MF catalyst leads to insertion of sulfur into thietane ring with the formation of the corresponding cyclic disulfides—3,3-bis(trifluoromethyl)-5-R-1,2-dithietanes. On the other hand, the addition of second mole of sulfur to the solution of 1 in DMF in the presence of CsF catalyst, followed by addition of vinyl ether results in exothermic reaction, and it produces the corresponding 2,2-bis(trifluoromethyl)-4-alkoxy-1,3-Dithiolanes in good yield. It was also demonstrated that 2,2-bis(trifluoromethyl)-4-R-thietanes can undergo disproportionation under action of fluoride anion, producing a mixture of the corresponding 1,2-dithiolane and CF2 C(CF3)CH2CFHOR. The nucleophilic attack of fluoride anion in this case proceeds selectively on the carbon of the thietane ring, bearing alkoxy group. The structure of 2,2-bis(trifluoromethyl)-4-R-thietanes forming as the result of 2 + 2 cycloaddition reaction between hexafluorothioacetone generated “in situ” from dimer 1 and vinyl ether was firmly supported by single crystal X-ray diffraction data, obtained for thietane bearing t-BuO-group.
Changjiang Yao - One of the best experts on this subject based on the ideXlab platform.
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oxidative cross esterification of Dithiolanes with alcohols through a cross dehydrogenative coupling cdc deprotection sequence
ChemInform, 2012Co-Authors: Changjiang Yao, Ningjie Chang, Jiarong Chen, Wenjing XiaoAbstract:The one-pot cross-dehydrogenative coupling—deprotection of Dithiolanes with primary and secondary alcohols proceeds smoothly in the presence of CuI as catalyst to give the corresponding carboxylic esters in high yields.
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oxidative cross esterification of Dithiolanes with alcohols through a cross dehydrogenative coupling cdc deprotection sequence
Organic and Biomolecular Chemistry, 2012Co-Authors: Changjiang Yao, Ningjie Chang, Jiarong Chen, Wenjing XiaoAbstract:An unprecedented oxidative cross-esterification in an equimolar mixture of Dithiolanes, alcohols and water through a CDC/deprotection sequence has been developed. The reaction itself features simple experimental procedures under very mild conditions and offers a new strategic protocol for the direct and efficient synthesis of structurally diverse esters.