4-alkyl(aryl)-1-germacyclohexa-2,5-diene

enThe 1(Z),4(Z)-1,5-dilithium-3R-3-methoxypenta-1,4-dienes react with diaryldichlorogermanes and dialkyldichlorogermanes to give the 1,1-diaryl- and 1,1-dialkyl-4R-4-methoxy-1-germacyclohexa-2,5-dienes, respectively.With phenyltrichlorogermane, methyl- and ethyl-trichlorogermanes the E/Z-isomeric 1-phenyl(methyl,ethyl)-1-chloro-4R-4-methoxy-1-germacyclohexa-1,3-dienes are obtained, reduction of these with LiAlH₄ makes the corresponding 1-aryl-(alkyl)-1H-4R-4-methoxy-1-germacyclohexa-2,5-dienes available.Reduction of 1-ethyl-1-chloro-4-phenyl-4-methoxy-1-germacyclohexa-2,5-diene with LiAlH₄ yields by additional ether cleavage 1-ethyl-1H-4-phenyl-1-germacyclohexa-2,4-diene.The ¹H NMR (60 MHz, 90 MHz), ¹³C NMR, IR and mass spectra are discussed, several ¹H NMR spectra are calculated according to the LAOCOONLAME program.     

Synthese und reaktionen von 1-germcyclohexa-2,4-dienen und 1-germacyclohexa-2,4-dien-eisentricarbonylen

1,1-Diakyl(aryl)4-alkyl(aryl)-4-methoxy-1-germacyclohexa-2,5-dienes undergo ether cleavage with sodium in n-pentane or liquid ammonia. Hydrolysis of the resulting sodium salts yields the 1,1-dialkyl(aryl)-4-alkyl(aryl)-1-germacyclohexa-2,4-dienes. Reduction of 1-chloro-4-methoxy-1-germacyclohexa-2,5-dienes with LiAlH₄ can be directed to give the 1H-1-germacyclohexa-2,4-dienes with ether cleavage.The 1H-1-germacyclohexadienes are chlorinated by PCl₅ and brominated by N-bromosuccinimide to the 1-chloro- or 1-bromo-1-germacyclohexa-2,4-dienes, respectively. 1,1-Diethyl-4-phenyl-4-methoxy-1-germacyclohexa-2,5-diene reacts with PCl₃ with ether cleavage and formation of the 6-chloro-1-germacyclohexa-2,4-diene. Ether cleavage is also possible with BCl₃, the 1-phenyl-1-chloro-4R-4-methoxy-1-germacyclohexa-2,5-dienes are transformed into the 1-phenyl-1,6-dichloro-4R-1-germacyclohexa-2,4-dienes.The Fe(CO)₃ complexes of 1,1-dialkyl(aryl)-1-germacyclohexa-2,4-dienes were synthesized.     

Silacyclohexadienylanionen bis- und tris-trimethylsilyl)-silacyclohexadiene

1,1-Dialkyl(1,1-diaryl)-4-R-1-silacyclohexadienyl anions (1) are available by ether cleavage of the corresponding, 1,1-dialkyl(1,1-diaryl)-4-methoxy-4-R-1-silacyclohexa-2,5-dienes (4), or by deprotonation of the 1,1-dialkyl(1,1-diaryl)-4-R-1-silacyclohexa-2,4-dienes (3) - which are available from 4 - with n-BuLi or LDA resp.The anions 1 are regioselectively silylated by trimethylchlorosilane to give the 6-trimethylsilyl-1-silacyclohexa-2,4-dienes (7,8), their alkylation or acylation occurs exclusively in 4-position to 16 or 17 resp.Deprotonation of 7, 8 with n-BuLi gives the 2-trimethylsilyl-1-silacyclohexadienyl (9), with trimethylchlorosilane they react regioselectively to give the 2,6-bis(trimethylsilyl)-1-silacyclohexa-2,4-dienes (10, 11), with alkyl halides and ketones the anion 9 reacts only in the 4-position.The 1-silacyclohexa-2,5-dienes 22, 25, 28 substituted at the silicon atom by functional groups (O-i-Prop) or by hydrogen can be transformed into 2,6-bis(trimethylsilyl)-1-silacyclohexa-2,4-dienes 24, 27, 33 resp., if LDA is used as base.The easily formed 4-R-2,6-bis(trimethylsilyl)-1-silacyclohexa-2,4-dienyl anions (by deprotonation of 10, 11, 24, 27, 33 with LDA) react with trimethylchlorosilane regioselectively to give the 4-R-2,4,6-tris(trimethylsilyl)-1-silacyclohexa-2,5-dienes 37. Accessing 37 succeeds very simply by manifold-silylation of the 1-sila-2,4-cyclohexadienes 38 with excess trimethylchlorosilane in the presence of 3 mol LDA.Owing to trimethylsilyl substitution in the 2,6-position of the 1-silacyclohexa-2,4-dienes, the ring-silicon atom is strongly sterically shielded, therefore reactions of functional groups at the silicon atom are restricted.     

Synthesis of new sulfanyl-, sulfinyl-, and sulfonyl-substituted polychlorobuta-1,3-dienes

New R-sulfanyl-substituted polychlorobuta-1,3-dienes were synthesized by reactions of hexachloro-1,3-butadiene or 1,1,2,4,4-pentachlorobuta-1,3-diene with dimethylbenzenethiols, heptane-1-thiol, and 4-methyl-7-sulfanyl-2H-chromen-2-one. Some sulfides were oxidized to the corresponding sulfoxides and sulfones or brominated with bromine. Among the synthesized compounds, the coumarin derivative, 4-methyl-7-(1,2,3,4,4-pentachlorobuta-1,3-dien-1-ylsulfanyl)-2H-chromen-2-one showed fluorescence properties. 1,1′,1″-[3,4-Dichlorobuta-1,3-diene-1,1,4-triyltris(sulfanediyl)]tris(2,4-dimethylbenzene) reacted with potassium tert-butoxide in petroleum ether to afford a mixture of isomeric 1,1′,1″-[4-chlorobuta-1,2,3-triene-1,1.4-triyltris(sulfanediyl)]tris(2,4-dimethylbenzene) and 1,1′,1″-[2-chlorobut-1-en-3-yne-1,1,4-triyltris(sulfanediyl)]-tris(2,4-dimethylbenzene). The GC/MS method was found to be useful for the separation of some sulfanyl-substituted butadiene isomer mixtures. The synthesized compounds were characterized by elemental analyses, mass spectrometry, UV-Vis, IR, and NMR (¹H, ¹³C) or fluorescence spectroscopy.     

Synthesis,structure, and conformation of terphenylene-derived azacalix[4]aromatics

Several novel azacalix[4]aromatics constituting terphenylene units have been synthesized via sequential nucleophilic aromatic substitution reactions of 5′-t-butyl-(1,1′:3′,1″-terphenyl)-3,3″-diamine 9 and 5′-t-butyl-(1,1′:3′,1″-terphenyl)– 4,4″-diamine 11 with 1,5-difluoro-2,4-dinitrobenzene and cyanuric chloride, respectively. The bridging –NH– functions of the tetra-nitro substituted azacalix[2]arene[2]terphenylenes 1 and 2 have been transformed to the corresponding –N(CH₃)– bridged azacalix[2]arene[2]terphenylenes 3 and 4 via N-alkylation. Single crystal X-ray analysis revealed that the terphenyl-3,3″-diamine derived azacalix[2]terphenylene[2]triazine 5 adopts a distorted chair conformation in the solid state, and the terphenyl-4,4″-diamine derived azacalix[2]terphenylene[2]triazine 6 was found to adopt a 1,3-alternate conformation.     

Five-membered 2,3-dioxo heterocycles: XCII. Reaction of 3-aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with ethyl (2Z)-(3,3-dimethyl-8-oxo-2-azaspiro[4.5]deca-6,9-dien-1-ylidene)ethanoate. Synthesis of bridged analogs of pyrrolizidine alkaloids

3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with ethyl (2Z)-(3,3-dimethyl-8-oxo-2-azaspiro[4.5]deca-6,9-dien-1-ylidene)acetate to give ethyl 6′-aryl-2′-(2-hydroxyphenyl)-11′,11′-dimethyl-3′,4,4′,13′-tetraoxospiro[2,5-cyclohexadiene-1,9′-(7′-oxa-2′,12′-diazatetracyclo[6.5.1.0^1,5.0^8,12]tetradec-5′-ene)]-14′-carboxylates whose structure was confirmed by X-ray analysis. The products may be regarded as bridged analogs of pyrrolizidine alkaloids, 7′-oxa-2′,12′-diazatetracyclo[6.5.1.01,5.08,12]tetradecanes.     

Dihalogencarben-cycloadditionen an 1-silacyclohexa-2.4-diene 4(5)-sila-bicyclo[4.1.0]-hept-2-ene

4R-1-silacyclohexa-2.4-dienes react with dichlorocarbene and dibromocarbene - prepared by phase-transfer catalysis - to give the cycloadducts at the 2.3- or 4.5- double bond, depending on the nature of R.Über Cycloadditionen von Carbenen an ungesättigte Sila- und Germa-heterocyclen liegen bislang nur wenige Untersuchungen vor.Nach D. Seyferth u. Mitarb. [1] werden bei der Reaktion von 1.1.3.4-Tetramethyl-1-silacyclopenten-3 mit Dichlorcarben (thermolytisch aus C₆H₅HgCCl₂Br) offenkettige Produkte erhalten, die allerdings auf eine vorangegangene Cycloaddition von CCl₂ schließen lassen.Bei der analogen Umsetzung von 1-Germacyclopentenen-3 [1] erhält man als Folgeprodukte der primär gebildeten Cyclopropanaddukte sowohl Germacyclohexadiene-2.4 - als Ergebnis einer Ringerweiterung - als auch Ringöffnungsprodukte. Die Cyclopropanderivate konnten von D. Seyferth u. Mitarb. [2] erst bei Einhaltung sehr milder Reaktionsbedingungen isoliert werden.     

Synthesis of methyl 4-aryl-4-oxo-2-[(4-sulfamoylphenyl)amino]but-2-enoates and their reaction with ninhydrin

The reaction of methyl 4-aryl-2,4-dioxobut-2-enoates with 4-aminobenzenesulfonamide in acetic acid–ethanol (1: 1) afforded methyl (2Z)-4-aryl-4-oxo-2-(4-sulfamoylanilino)but-2-enoates which reacted with ninhydrin in glacial acetic acid to give 3-aroyl-4-(4-sulfamoylanilino]-5H-spiro[furan-2,2′-indene]-1′,3′,5-triones.     

Synthese und reaktionen von zinn-substituierten pentadienderivaten

(1E, 4E)-1,5-Bis(trimethylstannyl)pentadiene-1,4 (III), 1E-1-trimethylstannyl-pent-1-ene-4-yne (IV) and the 1,1-dialkyl-1-stannacyclohexadienes-2,5 VII and VIII have been synthesized by hydrostannation of pentadiyne-1,4. (1E, 4E)1,5-Dibromapentadiene-1,3 (IX) is formed from III and 1,1,2,4,5,5-hexabromopentane (X) from IX by reaction with bromine. Butyllithium reacts with III to give (1E, 4E)-1,5-dilithium pentadiene-1,4 (XI). The reactions of butyl- and methyllithium with VII and VIII give only the monolithium compounds XIII, XV and XVII. All lithium compounds are characterised in the form of their trimethylsilyl derivatives XII, XIV, XVI and XVIII. ¹H NMR, IR, UV and mass spectral data are described.     

New Monoterpene-Substituted Dihydrochalcones from Piper aduncum

Five New unusual monoterpene-substituted dihydrochalcones, the adunctins A–E (1″S)-1-{2′-hydroxy-4′-methoxy-6′-[4″-methyl-1″-(1?-methylethyl)cyclohex-3″ -en-1″ -yloxy]phenyl}-3-phenylpropan-1-one ( 1 ), (5aR*,8R*,9aR*)-3-phenyl-1-[5′,8′,9′,9′a-tetrahydro-3′-hydroxy-1′-methoxy-8′-(1″-methylethyl)-5′-a-methyldibenzo-[b,d]furan-4′-yl]propan-1-one ( 2 ), (2′R*,4″S*)-1-{6′-hydroxy-4′-methoxy-4″-(1?-methylethyl)spiro[benzo[b]-furan-2′(3′H),1″ -cyclohex-2″ -en]-7′-yl}-3-phenylpropan-1-one ( 3 ), (2′R*,4″R*)-1-{6′-hydroxy-4′-methylethyl-4″-(1?-methylethyl)spiro[benzo[b]furan-2′(3′H),1″-cyclohex-2″-en]-7′-yl}-3-phenypropan-1-one ( 4 ), and (5′aR*,6′S*, 9′R*,9′aS*)-1-[5′a,6′,7′,8′,9′a-hexahydro-3′,6′-methoxy-6′-methyl-9′-(1″-methylethyl)dibenzo[b,d]-furan-4′-yl]-3-phenylpropan-1-one ( 5 ) were isolated from the leaves of Piper aduncum (Piperaceae) by preparative liquid chromatography. In addition, (?)-methyllindaretin ( 6 ), trans-phytol, and α-tocopherol ( = vitamin E) were also isolated and identified. The structures were elucidated by spectroscopic methods, including 1D- and 2D-NMR spectroscopy as well as single-crystal X-ray diffraction analysis. The antibacterial and cytotoxic potentials of the isolates were also investigated.     

Novel organomagnesium reagents in synthesis. Catalytic cyclomagnesiation of allenes in the synthesis of N-, O-, and Si-substituted 1Z,5Z-dienes

An efficient method for the synthesis of valuable N-, O-, and Si-containing 1Z,5Z-diene compounds was developed. The method comprises Cp₂TiCl₂-catalyzed homo- and cross-cyclomagnesiation of 1,2-dienes by Grignard reagents (RMgR′) to give 2,5-dialkylidenemagnesacyclopentanes in up to 96% yield. This approach was successfully used in the synthesis of 5Z,9Z-dienoic acids, precursors of acetogenins and insect pheromones.     

Synthesis of a New Naturally Occurring 3-Phenyl-4H-1-Benzopyran-4-One

7-Hydroxy-8-methoxy-3-(3,4-methylenedioxyphenyl)-4H-1-benzopyran-4-one (1), a new isoflavone reported to occur in the aerial parts and roots of Tephrosia maxima has been synthesized by the oxidative rearrangement of 2′-hydroxy-3′-methoxy-4′-benzyloxy-3,4-methylenedioxychalcone (4) with thallium (III) nitrate (TTN) in trimethyl orthoformate (TMOF), followed by acid catalysed cyclization and debenzylation. It has also been synthesized by another method from 2,3,4-trihydroxy-3,4′-methylenedioxydeoxybenzoin; the hitherto unknown biisoflavone, 7,7′-dimethoxy-3′,4″,3″,4″-dimethylenedioxy-8,8′-biisoflavonyl ether was also formed during this method.     

A facile method for the stereoselective preparation of (1E,3E)-4-substituted-1-amino-1,3-dienes via 1,4-elimination

The 1,4-elimination reaction of 1-amino-4-methoxy-(2Z)-alkenes is shown to proceed with high (1E,3E)-stereoselectivities to afford the corresponding 4-substituted-1-amino-1,3-dienes in good yield. The scope and stereochemical features of the synthetic method are described.     

Photochemische reaktionen von übergansmetall-olefinkomplexen: III. [4 + 6]-cycloaddition konjugierter diene an hexacarbonyl-μ-η6:6(-1,1′-bi(2,4,6-cycloheptatrien-1-yl)dichrom(O)

UV irradiation of hexacarbonyl-μ-η^6:6-1,1′-bi(2,4,6-cycloheptatrien-1-yl)dichromium(O) (I) in THF in the presence of 1,3-butadiene (A), E-1,3-pentadiene (B) and EE-2,4-hexadiene (C) causes preferentially a twofold [4 + 6]-cycloaddition and formation of the hexacarbonyl-μ-2–5 : 8.9-η-2′–5′ : 8′,9′-η-11,11′-bi(bicyclo-[4.4.1]undeca-2,4,8-trien-11-yl)dichromium(O) complexes (IVA–IVC). Partial decomplexation after the first [4 + 6]-cycloaddition yields isomeric tricarbonyl-2–5:8,9-η- (IIA–IIC) and tricarbonyl-2′–7′-η-{11-(2′,4′,6′-cycloheptatrien-1′-yl)bicyclo[4.4.1]undeca-2,4,8-triene}chromium(O) complexes (IIIA–IIIC). With 2,3-dimethyl-1,3-butadiene (D) mainly dicarbonyl-2–6 : 2′–4′-η-{1-(2′,3′-dimethyl-3′-buten-1′,2′-diyl)-7-(8″,9″-dimethylbicyclo[4.4.1]undeca-2″, 4″,8″-trien-11″-yl)cyclohepta-3,5-dien-2-yl}chromium(O) (VD) besides small amounts of pentacarbonyl-μ-2–6 : 2′–4′-η-2″–7″-η-{1-(2′,3′-dimethyl-3′-buten-1′,2′-diyl)-7-(2″, 4″,6″-cycloheptatrien-1″-yl)cyclohepta-3,5-dien-2-yl}dichromium(O) (VID) and tricarbonyl-2′-7′-η-{11-(2′,4′,6′-cycloheptatrien-1′-yl)-8,9-dimethyl-bicyclo[4.4.1]undeca-2,4,8-triene}-chromium(O) (IIID) is obtained. VD adds readily CO to yield tricarbonyl-2–5 : 8,9-η-11,11′-bi(8,9-dimethyl-bicyclo[4.4.1]undeca-2,4,8-trien-11-yl)chromium(O) (VIID). Finally D adds to VID under formation of pentacarbonyl-μ-2–6 : 2′–4′-η-2″–5″ : 8″,9″-η-{1-(2′,3′-dimethyl-3′-buten-1′,2′-diyl)-7-(8″,9″-dimethyl-bicyclo[4.4.1]- undeca-2″,4″,8″-trien-11″-yl)cyclohepta-3,5-dien-2-yl}dichromium(O) (VIIID). From IVA–IVC the hydrocarbon ligands (IXA–IXC) can be liberated by P(OCH₃)₃ in good yields. The structures of the compounds IIA–IXC were determined by IR     

Darstellung von PdCl2-komplexen substituierter cis,cis-cycloocta-1,5-diene aussachtringen und den entsprechenden substituierten cis-1,2-divinylcyclobutanen. cis,trans-zuordnung 3,4-,3,7- und 3,8-disubstituierter cis,cis-cycloocta-1,5-diene

cis-1,2-Divinylcyclobutanes are transformed with dibenzonitrilepalladium(II) chloride into the corresponding cis,cis-cycloocta-1,5-diene-PdCl₂ complexes. When e.g. the 3-methyl-cis,cis-cycloocta-1,5-diene-PdCl₂ complex is prepared using trans- or cis-3-methyl-cis-1,2-divinylcyclobutane or the corresponding eight-membered ring. two PdCl₂ complexes with the methyl group in the equatorial or axial position are formed in different percentages. With the aid of ¹H NMR spectroscopy the cis- or trans-configurations of 3,4-, 3,7- or 3,8-disubstituted cis,cis-cycloocta-1,5-dienes can be determined unambiguously in PdCl₂ complexes.     

Reactions of 1,4-diaza-3-methylbutadien-2-ylpalladium(II) derivatives with chloro-bridged rhodium(I) complexes

The reactions of the organometallic 1,4-diazabutadienes, RN=C(R′)C(Me)=NR″ [R = R″ = p-C₆H₄OMe, R′ = trans-PdCl(PPh₃)₂ (DAB); R = p-C₆H₄OMe, R″ = Me, R′ = trans-PdCl(PPh₃)₂ (DAB^I; R = R″ = p-C₆H₄OMe, R′ = Pd(dmtc)-(PPh₃), dmtc = dimethyldithiocarbamate (DAB^II); R = R″ = p-C₆H₄OMe, R′ = PdCl(diphos), diphos = 1,2-bis(diphenylphosphino)ethane (DAB^III)] with [RhCl(COD)]₂ (COD = 1,5-cyclooctadiene, Pd/Rh ratio = $\text{1}\text{2}$) depend on the nature of the ancillary ligands at the Pd atom in group R′. In the reactions with DAB and DAB^I transfer of one PPh₃ ligand from Pd to Rh occurs yielding [RhCl(COD)(PPh₃)] and the new binuclear complexes [Rh(COD) {RN=C(R?)-C(Me)=NR″}], in which the diazabutadiene moiety acts as a chelating bidentate ligand. Exchange of ligands between the two different metallic centers also occurs in the reaction with DAB^II. In this case, the migration of the bidentate dmtc anion yields [Rh(COD)Pdmtc] and [Rh(COD) {RN=C(R?)C(Me)=NR″}]. In contrast, the reaction with DAB^III leads to the ionic product [Rh(COD)- (DAB^III)][RhCl₂(COD)], with no transfer of ligands. The cationic complex [Rh(COD)(DAB^III)]⁺ can be isolated as the perchlorate salt from the same reaction (Pd/Rh ratio = 1/1) in the presence of an excess of NaClO₄. In all the binuclear complexes the coordinated 1,5-cyclooctadiene can be readily displaced by carbon monoxide to give the corresponding dicarbonyl derivatives. The reaction of [RhCl(CO)₂]₂ with DAB and/or DAB^I yields trinuclear complexes of the type [RhCl(CO)₂]₂(DAB), in which the diazabutadiene group acts as a bridging bidentate ligand. Some reactions of the organic diazabutadiene RN=C(Me)C(Me)=NR (R = p-C₆H₄OMe) are also reported for comparison.     

SCHWEFELDIIMIDE MIT SILYL-, GERMYL-, STANNYL- UND PHOSPHINYL-HETEROSUBSTITUENTEN. SYNTHESE UND NMR-SPEKTROSKOPISCHE CHARAKTERISIERUNG

Abstract

Reactions of the salts K₂SN₂ and K[(NSN)R] (R = ′Bu, SiMe₃ and P′Bu₂) with organoelement chlorides R′R′ěl have been used to prepare four series of model sulfur diimides: R′R″E(NSN)ER″R′, ′Bu(NSN)ER″R′, Me₃Si(NSN)E″R′ and ^tBu₂P(NSN)ER″R′, respectively (E = C, Si, Ge, Sn; R′ and R″ = alkyl or aryl group). All compounds have been characterized by ′H and ¹³C NMR and—if possible—by ³¹P, ²⁹Si and ¹¹⁹Sn NMR spectroscopy. The configuration (Z or E) of the substituents R and E″R′ has been assigned in several cases using ^tBu(NSN)^tBu (1) as a reference. The E,Z assignment of ¹H, ¹³C and ¹⁵N nuclei in 1 is based on selectively ¹H-decoupled refocused INEPT ¹⁵N NMR and two-dimensional (2D) ¹³C/¹H heteronuclear shift correlations. The sulfur diimides under study are in general fluxional in solution.     

Flavonoids of Ammothamnus lehmannii. Structure of lehmannin and of ammothamnidin

The new flavanon lehmannin (I) has been isolated from the roots ofAmmothamnus lehmannii Bunge. On the basis of chemical transformations and with the aid of physicochemical characteristics it has been established that compound (I) has the structure of 2′,4′,7-trihydroxy-8-(2″-isopropenyl-5″-methylhex-4″-enyl)flavanone. The alkaline cleavage of lehmannin gave ammothamnidin (V). The structure proposed previously for the chalcone ammothamnidin has been corrected. It has been shown that it has the structure of 2,2′-4,4′-tetrahydroxy-3′-(2″-isopropenyl-5″-methylhex-4″- enyl)chalcone. A comparative study of the¹³C NMR spectra of a number of flavanones has revealed an empirical law permitting the prediction of the presence or absence of substituents (OH and OCH₃) at C-2′ from the value of the chemical shift of the signal of the C-2 carbon atom.     

The UV photolysis (λ = 185 nm) of liquid t-butyl methyl ether

t-Butyl methyl ether has been UV photolysed (λ = 185 nm) to a maximal conversion of less than 0·1%. A study of the products (quantum yields) has been made: methanol (0·40₅), t-butanol (0·20), isobutene (0·17₈), t-butyl neopentyl ether (0·14₂), t-butyl ethyl ether (0·13₄), 1,2-di-t-butoxyethane (0·097), methane (0·056), isobutane (0·046), isopropenyl methyl ether (0·030), hydrogen (0·020), neopentane (0·016), ethane (0·015), formaldehyde (0·012), 2-methoxy-2-methyl-4-t-butoxybutane (0·005), hexamethylethane (0·0048), 2-methoxy-2-methylbutane (0·0027), 2-methoxy-2-methyl-3-t-butoxypropane (0·002), isopropyl methyl ether (0·0015), formaldehyde t-butyl methyl acetal (0·001), formaldehyde di-t-butyl acetal (0·001), 2-methoxy-2-methyl-4,4-dimethylpentane (0-001), 2-methoxy-2-methyl-3,3-dimethylbutane (0·0003), 2,5-dimethoxy-2,5-dimethylhexane (0·0002), di-t-butyl ether (5 · 10^?5), 2,2-dimethyloxirane (?, <- 0·001). There is no decomposition of the t-BuO radical into acetone (< 5 · 10^?4) and CH₃. Cyclisation reactions leading to α,α-dimethyloxetane (< 10^?4) and 1-methoxy-1-methylcyclopropane (< 10^?4) do not occur. The material balance yields C₅H_11·97O_1·018.The main modes of fragmentation (ca 82%) are represented by the homolytic CO bond split, either into t-butyl and methoxy (ca 52%) or into t-butoxy and methyl (ca 30%), Fragmentation into methanol and isobutene (8·5%) as well as into formaldehyde and isobutane (2%) are further modes of decomposition. The break of a CC linkage (4·5%) mainly occurs by elimination of molecular methane. A CH bond split has a probability of ca 3% with the methoxy CH bond the more likely one to break.     

Hexafluorothioacetone based synthesis of fluorinated heterocycles

Cycloadducts of hexafluorothioacetone (HFTA) were prepared in high yield by a CsF catalyzed reaction between readily available 2,2,4,4-tetrakis-(trifluoromethyl)-1,3-dithietane (as a source of HFTA) with conjugated electron-rich hydrocarbon dienes, such as cyclopentadiene, 2,3-dimethylbuta-1,3-diene, cyclohexa-1,3-diene or (1Z,3Z)-cyclohepta-1,3-diene. Cyclohexa-1,4- and (1Z,5Z)-cycloocta-1,5-dienes, also undergo the reaction with in situ generated HFTA, but form the products of insertion of HFTA into the C-H bond of the diene as a result of ene-reaction. The highly selective reaction of HFTA with (1Z,3Z,5Z)-cyclohepta-1,3,5-triene and (1Z,3Z,5Z,7Z)-cycloocta-1,3,5,7-tetraene leads to the formation of cycloadducts derived from exclusive addition of thioacetone to the corresponding bicyclic isomers—bicyclo[4.1.0]hepta-2,4-diene or bicyclo[4.2.0]octa-2,4,7-triene, respectively. The corresponding cycloadducts of HFTA with 2,3-dimethylbutadiene-1,3-cyclohexa-1,3-cyclohexa-1,4-dienes and (1Z,3Z,5Z)-cyclohepta-1,3,5-triene were also prepared by direct reaction of sulfur/hexafluoropropene/KF and the corresponding hydrocarbon substrate at 35-45 °C in DMF.