Aspects of stereoselectivity in electrophilic addition reactions of iodine with 5-allenyl-2,3,5-trichloro-4,4-dimethoxycyclopent-2-en-1-one and its derivatives

The reactions of 5-allenyl-2,3,5-trichloro-4,4-dimethoxycyclopent-2-en-l-one and related compounds with I₂ were studied. The stereochemistry of the resulting 1,2-adducts with I₂ at the terminal double bond of the allenic fragment depends in a complex way on the character of functionalization in the cyclopentene fragment of the starting molecule.     

Ozonolysis of Ricinolic Acid Derivatives and Transformations of the Ozonolysis Products under Barton Reaction Conditions

The possibility of functionalizing the alkyl part of ricinolic acid using the Barton reaction was investigated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 529–534, November–December, 2005.     

Reaction of 5-Allenyl-2,3,5-trichloro-4,4-dimethoxy-2-cyclopentenone and Its Derivative with Iodine

Allenyl-2,3,5-trichloro-4,4-dimethoxy-2-cyclopentenone and 5-allenyl-2,3,5-trichloro-4,4-dimethoxy-1-(2-propynyl)-2-cyclopentenol react with iodine in methylene chloride at room temperature to give the corresponding 5-[(E)-2,3-diiodo-1-propenyl] derivatives.     

Reaction of the N-mesylates of 1,3a,4,8b-tetrahydrocyclopenta[b]indoles and 3,4,4a,9a-tetrahydrocarbazoles with dimethyldioxirane and bromine

In reaction with dimethyldioxirane N-mesyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles and N-mesyl-3,3,4a,9a-tetrahydrocarbazoles mostly form the trans-epoxide. The reaction with molecular bromine leads to the product from halogenation in the aromatic ring, i.e., the corresponding N-mesyl-7-bromo-1,3a,4,8b-tetrahydrocyclopenta[b]indole or N-mesyl-6-bromo-3,4,4a,9a-tetrahydrocarbazole. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1306–1313, September, 2006.     

Hydroboration-oxidation of ricinoleic acid derivatives

The regioselectivity in the hydroboration-oxidation of ricinoleic acid derivatives only slightly depends on the configuration of the optically active center: the fraction of the resulting 1,3-diol is larger by 6–10% than that of the 1,4-isomer. The new asymmetric center has preferentially S configuration, as follows from the formation of the corresponding stereoisomeric 1,3-dioxane from the 1,3-diol and of 2,5-dialkyltetrahydrofuran from the 1,4-diol.     

Simple synthesis of substituted 3-oxabicyclo[3.1.0]hexan-2-ones and their rearrangement in the presence of lithium iodide

2-Alkenylidenemalonic ester monoepoxides react with organolithium and organomagnesium compounds to give 1-ethoxycarbonyl-4-alkyl-6-alkenyl(alkyl, aryl, alkynyl)-3-oxabicyclo[3.1.0]hexan-2-ones in high yields. The latter, when an alkenyl fragment is present, undergo rearrangement in the presence of LiI to substituted 1-ethoxycarbonyl-3-oxabicyclo[3.3.0]-6-octen-2-ones or 3-(1,3-butadienyl)-4-butanolides.Institute of Chemistry, Bashkir Science Center, Ural Branch, Russian Academy of Sciences, Ufa 450054. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 946–954, April, 1992.     

Unexpected transformation of methyl 3,6-anhydro-2,7-dideoxy-7-iodo-4,5-O-isopropylidene-D -allo-heptonate in the dehydroiodination reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene

The reaction of methyl 3,6-anhydro-2,7-dideoxy-7-iodo-4,5-O-isopropylidene-D-allo-heptonate with 1,8-diazabicyclo[5.4.0]undec-7-ene affords methyl 3,6-anhydro-2,7-dideoxy-4,5-O-isopropylidene-D-ribo-hept-6-enonate, which undergoes the previously unknown rearrangement into a 2,2-dimethyl-1,3-dioxole derivative. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2610–2613, November, 2005.     

Oxidation of N-acyl-2-(cycloalk-1-enyl)anilines with ozone and hydrogen peroxide

Treatment of the ozonization products from N-acetyl- or 2-methyl-N-trifluoroacetyl-6-(cyclopent-1-enyl)anilines with NaBH₄ gives 6-methyl-2-tetrahydropyranylaniline. When treated with Me₂S, the ozonization products yield the corresponding oxoaldehyde dimethyl acetals. The oxidation of N-acetyl-2-(cyclopent-1-enyl)- or -(cyclohex-1-enyl)anilines with H₂O₂ in HCOOH affords -(2-acetamidophenyl)-5-oxopentanoic or -6-oxohexanoic acid, respectively. The reaction of N-acetyl-2-(cyclopent-1-enyl)aniline with H₂O₂ in the presence of Na₂WO₄ and H₃PO₄ gives 3,1-benzooxazine in high yield.     

Synthesis of the Eleutheside Core from (+)- Δ-Cadinol: Construction of Side Chains on the Menthane Ring

Methods for allylic oxygenation of (+)--cadinol by SeO₂ have been developed to study approaches to the formation of the eleutheside core from it. Diasteromeric alcohols and the product of their 1,4-oxacyclization, which is transformed into a bicyclic derivative containing the required functional groups to study the final cyclization into the eleutheside core, were prepared. The -hydroxy derivative was converted after benzylation and ozonolysis into a mixed acetal, a convenient compound for performing the synthesis via an alternate route.     

Effect of low-lying collective states on the structure of giant resonances

The influence of coupling of the usual particle-hole states to particle-hole states built on a collective state has been estimated. Numerical calculations are performed for Ni⁶⁰Zr⁹⁰ and²⁰⁸Pb.