Manganese(III)-mediated intermolecular cyclization reactions of alkenes and active methylene compounds

The reactions of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methylphenyl)ethene, and 1,1-bis(4-methoxyphenyl)ethene with 3,5-diacetyl-2,6-heptanedione in the presence of manganese(III) acetate in acetic acid at 80° yielded 4,6-diacetyl-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes (41-48%), 5-acetyl-2,2-diaryl-6-methyl-2,3-dihydrobenzo[b]furans (20–21%), 3-acetyl-5,5-diaryl-2-methyl-4,5-dihydrofurans (5–10%), and benzophenones (3–7%). Similarly, the reactions of 1,1-diarylethenes with dimethyl 2,4-diacetyl-1,5-pentanedioate or diethyl 2,4-diacetyl-1,5-pentanedioate gave the corresponding 4,6-bis(alkoxycarbonyl)-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes in moderate yields.     

Simple NMR method for assigning relative stereochemistry of bridged bicyclo[3.n.1]-2-enes and tricyclo[7.n.1.0]-2-enes

The stereochemistry of syn and anti-forms of bridged bicyclo[3.n.1]-2-ene, tricyclo[7.n.1.0]-2-ene (n=1-3) and bicyclo[4.3.1]dec-7-ene derivatives can be assigned from the ¹³C chemical shift difference of the double bond. Both syn-9-R-bicyclo[3.3.1]non-2-enes and syn-13-R-tricyclo[7.3.1.0^2,7]tridec-2(7)-enes have a large shielding difference between sp² carbons, while the corresponding anti-forms have a smaller one. In contrast, 8-R-bicyclo[3.2.1]oct-2-enes and 12-R-tricyclo[7.2.1.0^2,7]dodec-2(7)-enes have an inverse correlation. The reason of this specificity is the influence of the γ-gauche effect on the chemical shift of C(2) atom. The GIAO theory has been applied to investigate the ¹³C chemical shifts. The conformational equilibrium in the formamide group of 13-formylamino-tricyclo[7.3.1.0^2,7]tridec-2(7)-enes has been studied.     

Synthesis of 6-alkylidene-2,3-benzo-1,4-diaza-7-oxabicyclo[4.3.0]non-2-enes by cyclization of 1,3-bis(silyl enol ethers) with quinoxalines

6-Alkylidene-2,3-benzo-1,4-diaza-7-oxabicyclo[4.3.0]non-2-enes were prepared by cyclization of 1,3-bis(silyl enol ethers) with quinoxaline.     

Synthesis of Substituted Trans-1,6-Dimethylbicyclo[4.3.0]-non-2-enes Using A Claisen Rearrangement of α-(Thioalkoxy) Esters

The Claisen rearrangement of α-(thioalkoxy)-esters provided access to substituted trans-1, 6-dimethylbicyclo[4.3.0]non-2-enes characteristic of the CD rings of the cucurbitanes.     

Synthesis,structure, and properties of pyrazolo[4,3-b]quinuclidine derivatives

It was shown by means of ¹H and ¹³C NMR spectroscopy that the reaction of 2-arylmethylene-3-oxoquinuclidines with hydrazine hydrate gives 4a-hydroxy-7-aryl-4a,5,7,7a-tetrahydropyrazolo[4,3-b]quinuclidines, which are stable in the crystalline state but undergo dehydration to the corresponding 7-aryl-6H-7,7a-dihydropyrazolo[4,3-b]quinuclidines in solutions. The latter undergo cleavage to 3-(4-piperidyl)-5-arylpyrazoles when they are heated in an alkaline medium.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1248–1256, September, 1985.     

Five-membered 2,3-dioxo heterocycles: LXXV. Reaction of methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates with 1,3-diphenylguanidine. Crystalline and molecular structure of 9-Benzoyl-8-hydroxy-2-imino-6-(4-methylphenyl)-1,3-diphenyl-1,3,6-triazaspiro-[4.4]non-8-ene-4,7-dione

Methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 1,3-diphenylguanidine to give the corresponding 6-aryl-9-aroyl-8-hydroxy-2-imino-1,3-diphenyl-1,3,6-triazaspiro[4.4]non-8-ene-4,7-diones. The molecular and crystalline structures of 9-benzoyl-8-hydroxy-2-imino-6-(4-methylphenyl)-1,3-diphenyl-1,3,6-triazaspiro[4.4]non-8-ene-4,7-dione were determined by X-ray analysis.     

Reaction of benzyne with cycloheptatriene preparation and thermolysis of some benzo(C9H10) hydrocarbons

The title reaction gave a 2+2 cycloadduct, 8,9-benzo-cis-bicyclo[5.2.0]nona-2,4,8-triene 7, together with ene product, 7-phenylcycloheptatriene. The structure of 7 was confirmed by catalytic reduction to give 8,9-benzo-cis-bicyclo[5.2.0]non-8-ene, which was also obtained in the reaction of benzyne with cycloheptene, and by reduction of the known 8,9-benzobicyclo[5.2.0]nona-1,8-diene. Other benzo(C₉H₁₀) hydrocarbons which have been synthesised are 7,8-benzobicyclo[4.2.1]nona-2,4,7-triene 5, 2,3-benzobicyclo[6.1.0]nona-2,4,6-triene 28 and 4,5-benzobicyclo[6.1.0]nona-2,4,6-triene 29. The thermolysis of 7, 28, 29 and of 3,4-benzo-exo-endo-tetracyclo[4.3.1.0^3,4.0^7,9]dec-3-en-10-one, 25, is described.     

Arylmethylene derivatives of 5-R-3H-furan-2-ones and N-aryl-5-R-3H-pyrrol-2-ones in reaction with acetylacetone

Reaction with acetylacetone in the series of 3-arylmethylene-substituted furan-2-ones and pyrrol-2-ones was studied. 8-R-4-Acyl-5-aryl-3-oxo-9-oxabicyclo[4.3.0]nona-1,7-dienes and N-tolyl-8-R-4-acyl-5-aryl-3-oxo-9-azabicyclo[4.3.0]nona-1,7-dienes were synthesized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1457–1462, October, 2007.     

SYNTHESIS AND REACTIONS OF 2,3-DIHYDRO- 5-ARYL-5H,6H-THIAZOLO[3,2-b]-2,4-DIAZAFLUORENE-3,6-DIONES OF POTENTIAL BIOLOGICAL ACTIVITIES

Abstract

1,2,3,4-Tetrahydro-l-aryl-3,9-dioxo-2,4-diazafluorenes (2) and 1,2,3,4-tetrahydro-1-aryl-9-oxo-3-thi-oxo-2,4-diazafluorenes (3) were newly synthesized. Compounds 3 reacted with chloroacetic acid, α-bromopropanoic acid, or B-bromopropanoic acid in the presence of fused sodium acetate and acetic anhydride to give 2,3-dihydro-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (4), 2-methyl-2,3-dihydro-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (5) and 2,3-dihydro-6-aryl-6H,7H-thiazino[3,2-b]2,4-diazafluorene-4,7-diones (6), respectively.

2,3-Dihydro-2-arylmethylene-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (7) were prepared by the reaction of compounds (3) with chloroacetic acid and aromatic aldehydes in the presence of fused sodium acetate and acetic anhydride or by the reactions of (4) with aromatic aldehydes in the presence of acetic anhydride.

2-(Arylhydroazono)-5-aryl-2,3-dihydro-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (8) were synthesized by coupling (4) with aryldiazonium salts in the presence of pyridine.     

Synthesis of perfluorobicyclic ethers [2]. The electrochemical fluorination of α-cyclohexenyl-substituted carboxylic acid derivatives

The electrochemical fluorination of α-cyclohexenyl-substituted carboxylic esters [

; R′CH₃, C₂H₅, C₃H₇)] afforded both perfluoro(9-alkyl-7-oxa-bicyclo[4.3.0]nonane)s and perfluoro(8-alkoxy-9-alkyl-7-oxabicyclo[4.3.0]nonane)s in fairly good yields. As the driving force for the ring-closure in this fluorination, a mechanism which involves a resonance stabilized intermediate radical is proposed. Perfluoro(8-chloro-8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) and perfluoro(8,8-dichloro-9-ethyl-7-oxabicyclo[4.3.0]nonane) were obtained by the controlled chlorination of perfluoro(8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) with anhydrous aluminum chloride in low yields. Some new fused perfluorobicyclic ethers and a perfluoroacid fluoride obtained in this experiment have been characterized by infrared, mass and ¹⁹F nmr spectra and elemental analysis.     

Reactions of Aliphatic Diazo Compounds: IV. Reaction of Diphenyldiazomethane with Substituted Imides of Maleic and Itaconic Acids

Diphenyldiazomethane regioselectively adds to 2-R-substituted maleimides to yield 1-pyrazoline derivatives, 1-R-7-aryl-6,8-dioxo-4,4-diphenyl-2,3,7-triazabicyclo[3.3.0]oct-2-enes that on heating liberate nitrogen to afford substituted 3-azabicyclo[3.1.0]hexanes. To the N-arylsubstituted imides of itaconic acid the diphenyldiazomethane adds to furnish 5-aryl-4,6-dioxo-1,1-diphenyl-5-azaspiro[2.4]heptanes.     

Reactions of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-2-enes and 1,2,7-Triazaspiro[4.4]non-1-enes with Halogens

Halogenation of 1-substituted 7-aryl-2,3,7-triazabicyclo[3.3.0]oct-2-ene-6,8-diones gives different products, depending on the substituent in position 1 (R¹): when R¹ = Ar, 6-chloro-3-azabicyclo[3.1.0]hexanes are formed, while compounds with R¹ = H or Me give rise to 2- or 4-chloro-2,3,7-triazabicyclo[3.3.0]oct-2-ene-6,8-diones whose thermolysis leads to formation of the corresponding 6-chloro-3-azabicyclo[3.1.0]hexanes. Chlorination of 7-aryl-1,2,7-triazaspiro[4.4]non-1-ene-6,8-diones yields 3-chloro-1,2,7-triazaspiro[4.4]non-1-ene-6,8-diones, and thermolysis of the latter affords 1-chloro-5-azaspiro[2.4]heptanes.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 78–88.Original Russian Text Copyright © 2005 by Molchanov, Stepakov, Kostikov.     

Photochemische Umwandlungen, 42 [1] Photoisomerisierungen im 5-Isopropyliden-tetracyclo-[4.3.0.02,4.03,7]non-8-en-System. Vorläufige mitteilung

Direct photochemical excitation of the tetracyclo[4.3.0.0.^2,4.0^3,7]non-8-enes 7a – d leads to a mixture of the isomers 8a – d and 10a – d , with the former being the main products. On sensitization by acetone the formation of 10a – d is clearly favored. The cis-bishomobenzenes 9a – d are the postulated intermediates. Spectral data and some thermal reactions are described.     

Radical deoxygenation of 3-azatricyclo[2.2.1.0]heptan-5-ols to 2-azabicyclo[2.2.1]hept-5-enes and 1,2-dihydropyridines

Additions of alkyl or aryl Grignard reagents, or pyridin-3-yl-lithiums or lithium alkoxides, to exo-5,6-epoxy-7-(tert-butoxycarbonyl)-2-tosyl-7-azabicyclo[2.2.1]hept-2-ene lead to 7-substituted-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols. Radical deoxygenations of 7-alkyl-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols give 7-alkyl-4-tosyl-2-azabicyclo[2.2.1]hept-5-enes, whereas 7-aryl-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols give 2-(arylmethyl)-5-tosyl-1,2-dihydropyridines.     

Rhodium(I)-catalyzed intramolecular pauson-khand-type [2 + 2 + 1] cycloaddition of allenenes

[reaction: see text] The novel [RhCl(CO)(2)](2)-catalyzed [2 + 2 + 1] cycloaddition of allenenes leading to the bicyclo[4.3.0]non-1(9)-en-8-one as well as the bicyclo[5.3.0]dec-1(10)-en-9-one skeletons has been developed. This method also provides a new procedure for the construction of the bicyclo[4.3.0]non-1(9)-en-8-one skeleton having an alkyl appendage at the ring juncture, which was hardly attained in a satisfactory yield by the Pauson-Khand reaction of the corresponding enynes.     

Tetraacetylethylene and nitrile oxides: Synthesis of spirofuranisoxazoles

trans and cis-3-Hexen-2,5-dione, 2 , reacted with nitrile oxides to give 4,5-dihydroisoxazoles 3a-c with the trans configuration. On the contrary the reaction between 3,4-diacetyl-3-hexen-2,5-dione, 1 , with nitrile oxides yielded 3-aryl-8,9-diacetyl-7-hydroxy-7-methyl-1,6-dioxa-2-azaspiro[4.4]nona-3,8-dienes 9a-e. The reaction is completely regiospecific. The cycloadducts show ring-open chain tautomerism.     

Proof of the Absolute Configuration of (−)-(S)-2-Hydroxy-β-ionone by correlation with ursolic acid and with (−)-trans-verbenol

(?)-(S)-2-Hydroxy-β-ionone ( 33 ), (+)-(2 S, 6 S)-2-hydroxy-α-ionone ( 34 ), and their acetates 35 and 36 have been synthesized from (+)-(S)-6-methylbicyclo [4.3.0]-non-1-ene-3, 7-dione ( 3 ). The key intermediate (+)-(1 R, 3 S, 6 S)-2, 2, 6-trimethyl-7-oxobicyclo [4.3.0]non-3-yl acetate ( 7 ) was correlated with a degradation product of the pentacyclic triterpene ursolic acid ( 16 ). Compound 33 was also synthesized by an alternative route starting from (?)-trans-verbenol ( 42 ).     

(6′RS,8′RS,2E)- und (6′RS,8′SR,2E)-3-Methyl-3-(2y,2′,6′-trimethyl-7′-oxabicyclo[4.3.0]non-9′-en-8′-yl)-2-propenal ([(5RS,8RS)- und (5RS,8SR)-5,8-Epoxy-5,8-dihydro-ionyloinden]acetaldehyd): Synthese und Röntgenstrukturanalyse

Synthesis and X-Ray Structure of (6′RS,8′RS,2E)- and (6′RS,8′SR,2E)-3-Methyl-3-(2′,2′,6′-trimethyl-7′-oxabicyclo[4.3.0]non-9′-en-8′-yl)-2-propenal ([(5RS,8RS)- and (5RS,8SR)-5,8-Epoxy-5,8-dihydro-ionylidene]acetaldehyde) To check our previous spectroscopic assignments of the structures of trans- and cis-substituted furanoid end groups of carotenoid-5,8-epoxides, we now have synthesized the title compounds. An X-ray structure determination of a single crystal of the trans-isomer (±)- -10A is in agreement with the ¹ H-NMR spectroscopic arguments: isomers with Δδ (H? C(7), H? C(8)) = 0.15–0.22 ppm and J > 1.4 for H? C(7) belong to the cis-series; Δδ in trans-compounds is < 0.07 ppm, and H? C(7) appears as a broad singulett.     

Reactions of Aliphatic Diazo Compounds: V. Reaction of Methyl Diazoacetate with Imides of Itaconic Acid

Methyl diazoacetate regioselectively adds to N-substituted imides of itaconic acid to afford 2-pyrazolines, methyl 7-aryl-6,8-dioxo-1,2,7-triazaspiro[4.4]non-2-ene-3-carboxylates that in reaction with halogens (Cl₂, Br₂) yield methyl 5-aryl-1-halo-4,6-dioxo-5-azaspiro[2.4]heptane-1-carboxylates as a mixture of syn- and anti-isomers.     

1a,11b-dihydrobenz[5,6]anthr[1,2-B]azirine. A non k-region polycyclic arene imine

The synthesis of the title compound 9 is described. Benz[a]anthracene 8,9-oxide (6) was reacted with sodium azide in aqueous acetone and the trans-9-azido-8,9-dihydrobenz[a]anthr-8-ol (7), so formed, was cyclized by tri-n-butylphosphine. Attempts to dehydrogenate 10,11-dihydrobenz[a]anthracene 8,9-imine (4) with DDQ or by allylic bromination followed by base assisted dehydrobromination was unsuccessful. The N-tosyl derivative of 4, prepared from the free imine, N,O-bis(trimethylsilyl)acetamide and tosyl chloride underwent rapid aziridine-ring cleavage by the silylating agent to give trans-8,9,10,11-tetrahydro-8-(4-methyl)benzensulfon-amido-9- [(trimethyl)oxy]benz[a]anthracene (10).