bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 2,11-Dehydrohomoadamantane (Tetracyclo[5.3.1.02,4.03,9]undecane) and 2,11-Dehydrohomoadamant-4-ene (Tetracyclo[5.3.1.02,4.03,9]undec-5-ene)
Authors: Katsushima Takeo , Maki Ken’ichiro , Yamaguchi Ryohei , Kawanisi Mituyosi 
Published: July 2006

Abstract
Bromination of tricyclo[5.3.1.04,9]undeca-2,5-diene gave endo-2,endo-6- and endo-2,exo-6-dibromotetracyclo[5.3.1.03,5.04,9]undecanes along with syn-11,endo-2-dibromotricyclo[4.3.1.13,8]undec-4-ene (10a) in a ratio of 3:3:1. A thermal treatment of the mixture of these dibromides at 140–150 °C induced a skeletal rearrangement to afford 10a and syn-11,exo-2-dibromotricyclo[4.3.1.13,8]undec-4-ene (10b) in 87% yield (10a:10b=2:5). The new “non-bridgehead” 2,11-dehydrohomoadamantane was obtained by the hydrogenation of 10a and 10b followed by Wurtz type reductive cyclization. The unsaturated analogue, 2,11-dehydrohomoadamant-4-ene was also synthesized from 10a and 10b by the similar cyclization reaction.
The Chemistry of Phenalenium Systems. XXXI. The Synthesis, Dimerization, and Trapping of 6-Methylenebenzo[cd]pyrene
Authors: Hara Osamu , Yamamoto Kagetoshi , Murata Ichiro 
Published: July 2006

Abstract
The acetolysis of 6-mesyloxymethyl-6H-benzo[cd]pyrene (6) gave 7,7a-dihydrospiro[benzo[ghi]perylene-5-(6H),6′-[6H]benzo[cd]pyrene] (13), whereas, on formolysis, 6 gave spiro[benzo[ghi]perylene-5(6H),6′-[6H]benzo[cd]-pyrene], 6-hydroxymethyl-6H-benzo[cd]pyrene, and 6-methyl-6H-benzo[cd]pyrene as well as 13. It might reasonably be supposed that the formation of 13 proceeds in a process involving four steps: (i) the formation of the intermediate 6H-6-benzo[cd]pyren-6-ylmethyl cation (8); (ii) the conversion of 8 into the reactive 6-methylenebenzo[cd]pyrene (5) by the loss of a proton; (iii) the head-to-head self-Diels-Alder dimerization of 5 to the initial dimer, 6,7-dihydrospiro[benzo[ghi]perylene-5(4aH),6′-[cd]benzo[cd]pyrene], and (iv) a 1,3-hydrogen shift to form 13. When 6-methylbenzo[cd]pyren-6-yl tetrafluoroborate (7) was treated with triethylamine in chloroform, the spiro-dimer, 13, was also obtained. The reaction of 7 with triethylamine in the presence of dimethyl acetylenedicarboxylate resulted in the formation of dimethyl benzo[ghi]perylene-5,6-dicarboxylate. These results strongly suggest the intermediate formation of 5 as a reactive compound.
Carbocyclic Ring Formation by the Intramolecular Reaction between Enol Silyl Ether and Allylic Acetate Moieties
Authors: Itoh Akira , Oshima Koichiro , Yamamoto Hisashi , Nozaki Hitosi 
Published: July 2006

Abstract
The title reaction of trans-3-acetoxy-4-(4-methyl-3-trimethylsiloxy-3-pentenyl)cyclohexene proceeds in the presence of Et2AlOAr, where Ar=2,6-di-t-butyl-4-methylphenyl, affording stereospecifically the cis isomer of 2,2-dimethylbicyclo[4.4.0]dec-9-en-3-one. In contrast, the cis-disubstituted cyclohexene compound reacts only sluggishly to produce a mixture of the cis- and trans-fused octalones. Similar stereospecific effect of the allylic double bond configuration on the ease of cyclization has been observed in the synthesis of karahanaenone from 3,7-dimethyl-6-trimethylsiloxy-2,6-octadienyl acetate and related reactions.
New Application of Crown Ethers. III. Synthesis of 4′-Hydroxybenzocrown Ethers and Their Bis(benzocrown ether)s Linked by Poly(oxyethylene) Chain
Authors: Wada Fumio , Arata Ryozo , Goto Tokio , Kikukawa Kiyoshi , Matsuda Tsutomu 
Published: July 2006

Abstract
Baeyer-Villiger oxidation of 4′-acetylbenzocrown ethers followed by alkaline hydrolysis was proved to be a convenient route to 4′-hydroxybenzo-15-crown-5 and -18-crown-6, which formed air-stable hydrated crystals containing three and one mole of water, respectively, on crystallization from the solvent containing a small amount of water. New bis(benzocrown ether)s, connected by poly(oxyethylene) chain, were obtained in good yields by the reaction of the sodium salts with the ditosylates of di-, tri-, tetra-, and pentaethylene glycol.
Kinetic Studies of Co(II)–Malonate, Malate, and Glycolate Complex-formation Reactions in Aqueous Solutions by the Pressure-shock Method
Authors: Harada Shoji , Kawasawa Masuo , Yasunaga Tatsuya 
Published: July 2006

Abstract
A pressure-shock apparatus applicable for the kinetic studies of rapid reactions in solution was constructed and used to study Co(II)–carboxylate complex-formation reactions. The chelate complex-formation reaction was interpreted in terms of a step-by-step mechanism, and the rate constants were obtained. The chelate-ring closing-and-opening process was revealed to be the rate-determining step.
ESR Spectra of Mn(II) Ions in Reversed Micellar Systems
Authors: Sen\={o} Manabu , Sawada Kiyoshi , Araki Koji , Kise Hideo , Iwamoto Kazutoshi 
Published: July 2006

Abstract
ESR spectra of hexaaqua complex of Mn(II) in a hexadecyltrimethylammonium bromide (HTAB)/chloroform reversed micellar system are studied. The structure of the Mn(II) complex is distorted at low water concentrations because of the dehydration due to the lack of water molecules available for the complexes. The effect of dehydration of metal ions on their catalysis for ATP hydrolysis is discussed.
The Photochemical Behavior of 3,3-Dimethyl-1,2-indanedione toward Aromatic Aldehydes
Authors: Maruyama Kazuhiro , Naruta Yoshinori , Osuka Atsuhiro , Suzuki Hitomi 
Published: July 2006

Abstract
The photochemical reaction of 3,3-dimethyl-1,2-indanedione with aromatic aldehydes in benzene was found to give a mixture of two diastereoisomeric 2:2 adducts, a 1:1 adduct, a 2:1 adduct, and pinacol.
Formation of C–S Bond by the Elimination of Perfluorocarboxylic Acid
Authors: Kawa Hajimu , Ishikawa Nobuo 
Published: July 2006

Abstract
Thiirane was readily generated from 2-mercaptoethyl trifluoroacetate or pentafluoropropionate by the intramolecular elimination of the perfluorocarboxylic acid with triethylamine. Alkyl benzyl sulfides were also prepared from benzyl trifluoroacetate or pentafluoropropionate and alkanethiols by the intermolecular elimination of the perfluorocarboxylic acid
Solubility of Some Organic Mercury(II) Halides in Water
Authors: Tajima Kooji , Kai Fumiaki , Kawahara Tetsuo 
Published: July 2006

Abstract
The solubilities of methylmercury(II) chloride (MMC), methylmercury(II) bromide (MMB), methylmercury(II) iodide (MMI), ethylmercury(II) chloride (EMC), and ethylmercury(II) bromide (EMB) in water have been determined over the temperature range of 10–55 °C (20–40 °C for MMC and EMC). The temperature dependence of the solubilities expressed as mole fractions x2 was given by the following equations:
& logx_2(MMC)=-1059/T+0.176 (20–40°C)
& logx_2(MMB)=-1094/T-0.263 (10–55°C)
& logx_2(MMI)=-463/T-3.246 (10–25°C)
& logx_2(MMI)=5.498×10^6(1/T)^2-3.711×10^4(1/T)+57.814 (25–55°C)
& logx_2(EMC)=-1048/T-0.612 (20–40°C)
& logx_2(EMB)=-179/T-4.293 (10–25°C)
& logx_2(EMB)=5.389×10^6(1/T)^2-3.603×10^4(1/T)+55.322 (25–55°C)
The thermodynamic parameters for the transfer process from solid to saturated aqueous solution were also determined.
Kinetic and Spectrophotometric Studies of Rhodamine 6G Dimerization in Aqueous Solution
Authors: Inaoka Wataru , Harada Shoji , Yasunaga Tatsuya 
Published: July 2006

Abstract
The dimerization reaction of dye, Rhodamine 6G, in aqueous solution was studied spectrophotometrically and kinetically: the equilibrium constant and the rate constants were found to be K=1.6×103 M−1, kf=1.1×109 M−1 s−1, and kb=7.0×105 s−1, respectively, at 15 °C. These rate constants, and those of other dyes are discussed. The effect of the ionic strength was also studied.
Thermal Desorption of Hydrogen Adsorbed on Copper Surface
Authors: Kojima Isao , Kiyomiya Makoto , Yasumori Iwao 
Published: July 2006

Abstract
The thermal desorption of hydrogen adsorbed on a clean surface of polycrystalline copper foil was studied under ultra high vacuum conditions. The presence of chemisorbed hydrogen in a dissociated state was verified in a temperature range between 193 and 573 K. During the desorption process, the adsorbed hydrogen atoms recombined into molecules; this follows second order kinetics. The activation energy for desorption was 68.6±8.0 kJ mol−1 and remained nearly constant in the range of surface coverage up to 1.6×1014 atom cm−2. The isotope effect on the desorption of deuterium was found to be straightforward. These findings showed a good agreement with the results obtained from the analysis of H2–D2 equilibration on copper powder catalyst. In addition, the necessary conditions to obtain the exact desorption spectra were inspected with the aid of computer simulation.
The Thermal Unimolecular Decomposition of Methyl Chloride behind Shock Waves
Authors: Kondo Osamu , Saito Ko , Murakami Ichiro 
Published: July 2006

Abstract
The thermal decomposition of methyl chloride diluted in Ar has been studied behind shock waves over the temperature range between 1680 and 2430 K and the total density range of 2.0×10−6–3.5×10−5 mol cm−3. The decomposition rate was monitored by means of the UV absorption of the CH3 radical produced. The initiation reaction was found to be the C–Cl bond fission; the process proceeded in the fall-off region under the present experimental conditions. From the fall-off data, low- and high-pressure rate constants (k0/[Ar] and k∞) were obtained by the application of a refined RRKM theory involving a weak collision effect. Thus, the Arrhenius expressions were given as:
& k_0/[Ar]=10^15.56 exp(-247 kJ mol^-1/RT) cm^3 mol^-1 s^-1,
& k_∞=10^13.86 exp(-383 kJ mol^-1/RT) s^-1.
The collision efficiency factor, βc, was obtained as 0.02 at the mean temperature of the experiment by comparing the low-pressure rate constant with the strong collision-rate constant. The high-pressure rate constant was well explained by the maximum free-energy criterion presented by Quack and Troe.
Homogeneous Hydroformylation of Methyl Acrylate Catalyzed by Co2(CO)8–Di(tertiary phosphine) Complexes
Authors: Murata Kazuhisa , Matsuda Akio 
Published: July 2006

Abstract
Some complexes prepared in situ from Co2(CO)8 and various di(tertiary phosphine)s as ligands have been found to be more active than Co2(CO)8 for the hydroformylation of methyl acrylate. The activity decreased in the order; Ph2P(CH2)2PPh2&gt;Ph2PC≡CPPh2&gt;cis-Ph2PCH=CHPPh2&gt;Ph2P(CH2)3PPh2&gt;none&gt;Ph2PCH2PPh2&gt;Ph2P(CH2)4PPh. The most active catalyst (I) was obtained when a molar ratio of Ph2P(CH2)2PPh2 to Co2(CO)8 was ca. 0.5. The catalyst (I) is also active even at low pressure, where the decomposition of Co2(CO)8 occurs.
Partner Orbitals in Hartree-Fock Theory
Authors: Hirao Kimihiko 
Published: July 2006

Abstract
The orbital ambiguity in the Hartree-Fock theory is removed in such a way as to improve the convergence property of the configuration interaction calculation. A practical proposal is made to obtain efficient orbitals for use in construction of wavefunctions. These orbitals are called the zeroth-order natural orbitals and their partner orbitals. It is also demonstrated by an illustrative calculation that use of partner orbitals rather than SCF orbitals gives much more rapid convergence and greater physical insight.
MO Calculation of Some Aromatic Radicals. Geometry and Spin Density of Benzyl Radical
Authors: Amano Toshihiro , Osamura Yoshihiro , Kai Eiko , Nishimoto Kichisuke 
Published: July 2006

Abstract
The geometry of benzyl radical, nitrobenzene anion-, benzaldehyde anion-, aniline cation-, and phenol cationradicals is optimized by means of the energy gradient method in the framework of the CNDO/2 method, and used for the calculation of spin densities by the INDO-UHF method. The geometrical change from a neutral molecule to the ion radical can be understood by considering the shape of particular MO’s. It was found that the molecular structure of benzyl radical is not a regular hexagon, the contraction of C1–C7 bond being remarkable. The correct order of the spin densities on ortho(ρ2)- and para (ρ4)-positions is obtained by the full geometry optimization. The structure of the deformed ring of benzyl radical is discussed in terms of the orbital mixing rule.
Light Scattering Study of Local Structures in Solutions. Mean Association Numbers and Concentration Fluctuations for Alcohol–Carbon Tetrachloride Systems
Authors: Kato Tadashi , Nakanishi Toru , Fujiyama Tsunetake 
Published: July 2006

Abstract
Light scattering spectra were observed for carbon tetrachloride solutions of methanol, ethanol, and 1-propanol. The Rayleigh intensities were reduced to concentration fluctuations. The observed concentration dependence of the concentration fluctuation was analyzed by using two distinct models: an ideal associated complex (IAC) model and a polymer chain (PC) model. In the IAC model, a group of hydrogen-bonded alcohol molecules is treated as a complex whose size is independent of the association number, l. In the PC model, on the other hand, the group of hydrogen-bonded molecules is treated as a linear polymer whose length is proportional to l. It was shown that the PC model can explain both the concentration fluctuation and the heat of mixing data, while the IAC model cannot be applied to the present systems. The mean association number obtained by the IAC model was discussed on the basis of the relation between the concentration fluctuation and the spatial correlation of microscopic density.
Reaction of Halogenonitrobenzenes with Electro-generated Superoxide Ion
Authors: Sagae Hiromitsu , Fujihira Masamichi , Komazawa Katsutaro , Lund Henning , Osa Tetsuo 
Published: July 2006

Abstract
The reaction of halogenonitrobenzenes (XNBs) with electrogenerated superoxide ion in N,N-dimethylformamide was studied electrochemically using cyclic voltammetry (CV) and controlled potential macro-electrolysis. It was shown in the CV that electro-generated superoxide ion reacts with all of the o- and p-isomers of iodo-, bromo-, and chloronitrobenzene in the dissolved oxygen medium. However the superoxide ion did not react with the other XNBs during CV. Controlled potential macro-electrolysis of oxygen in the presence of o- and p-bromonitrobenzene yielded the corresponding nitrophenols as the main products. The reaction mechanism via nucleophilic attack of the superoxide ion on the XNB, in the preference to an electron-transfer mechanism, is proposed.
Direct Observation of the 1,4-Biradical of Benzophenone with cis-3-Methyl-2-pentene Excited by the Fourth Harmonic of a Nd:YAG Laser
Authors: Hayashi Hisaharu 
Published: July 2006

Abstract
Intermolecular biradical formation between the benzophenone triplet state with cis-3-methyl-2-pentene was studied by a ns laser-photolysis technique, the fourth harmonic (266 nm) of a Q-switched Nd : YAG laser being used as an exciting light source. We succeeded for the first time in observing the transient absorption due to the 1,4-biradical in the 380–300 nm region. Its lifetime was determined to be 25±4 μs (in acetonitrile), 15±4 μs (in methanol), and 6±2 μs (in cyclohexane). Quenching experiments with methyl viologen dication were also carried out in order to assign the observed transient absorptions.
Studies on the Aqueous Solutions of Guanidinium Salts. XIII. NMR Study of the Interactions between Guanidinium Salt and Tetraalkylammonium Salts in Water
Authors: Miyajima Koichiro , Yoshida Hiromitsu , Kuroda Yoshihiro , Nakagaki Masayuki 
Published: July 2006

Abstract
The quadrupole relaxation of 14N nucleus of guanidinium bromide has been measured in aqueous ternary solutions containing symmetrical tetraalkylammonium salts by the 1H NMR method. By means of Pople’s line shape analysis and the Debye-Einstein equation, it has been confirmed that no complex formation takes place in the aqueous ternary solution containing symmetrical tetraalkylammonium salts. The rotational correlation time of the guanidinium ion is linearly related to the absolute viscosity of the solutions containing the homologous series of alkylammonium salts. A similar relationship was obtained for the ternary solutions with sugars or polyethylene glycols. This suggests that the correlation time depends on the microviscosity around the guanidinium ion.
The Use of Grignard Reagents in the Synthesis of Carbohydrates. I. The Synthesis of Deoxy and Branched-chain Deoxy Sugars
Authors: Kawana Masajiro , Emoto Sakae 
Published: July 2006

Abstract
Two branched-chain deoxy sugars, methyl 5,6-O-cyclohexylidene-3-deoxy-2-C-methyl-β-d-arabino-hexofuranoside and its α-d-ribo isomer, were easily prepared by the one-step reaction of methyl 5,6-O-cyclohexylidene-3-O-mesyl-β-d-allofuranoside (3a) with methylmagnesium iodide. Similarly, the corresponding α-mesylate (4a) gave methyl 5,6-O-cyclohexylidene-3-deoxy-2-C-methyl-α-d-ribo-hexofuranoside. It was demonstrated that these reactions involved 1,2-hydride shifts. The reaction of 3a and 4a with t-butylmagnesium bromide yielded two deoxy sugars, methyl 5,6-O-cyclohexylidene-3-deoxy-β-d-arabino-hexofuranoside and the corresponding α-d-ribo isomer, respectively. Under certain reaction conditions with the Grignard reagents, the sulfonate (3a) afforded dimeric compounds, in which two furanose rings were directly bound with a carbon–carbon bond. A convenient method for the preparation of the sulfonates (3a and 4a) is also reported.
Three-dimensional Metal Complex Structures with Ambident Propylene-diamine Ligands Serving as the Hosts of the Aromatic Guest Molecules. Hofmann-pn and pn-Td Type Clathrates
Authors: Nishikiori Shin-ichi , Iwamoto Toschitake , Yoshino Yukichi 
Published: July 2006

Abstract
Novel clathrate compounds, Hofmann-pn type Cd(pn)Ni(CN)4·3/2G (G=C4H5N, C4H4S, or C6H6) and pn-Td type Cd(pn)Cd(or Hg)(CN)4·3/2C6H6, have been prepared. Their host structures are analogous to those of the known Hofmann-en type Cd(en)Ni(CN)4·2G and en-Td type Cd(en)Cd(or Hg)(CN)4·2C6H6. The propylenediamine (pn: 1,2-diaminopropane) molecule ambidently bridges six-coordinate Cd atoms, as the en (ethylenediamine) does in the latter types of clathrates. The guest molecules occupy at random three quarters of the cavities in the host structures: every remaining cavity contains two methyl groups of the pn molecules. The crystal structure of Cd(l-pn)Ni(CN)4·3/2C4H5N has been analyzed in order to demonstrate the structural features. The crystal is tetragonal with the space group P422, a=7.575(2) and c=7.742(2) Å, and Z=1. The degree of disorder is extremely high with regard to the arrangement and orientation of the l-pn molecule.
Non-covalent Interactions in Metal Complexes. II. Induction of Asymmetry in Cobalt(III) Complexes with Amino Acid–Schiff Bases. Importance of CH···π-Interaction in Determining Configuration of Complexes
Authors: Okawa Hisashi , Numata Yoshihiko , Mio Ayako , Kida Sigeo 
Published: July 2006

Abstract
Cobalt(III) complexes, [Co(l-mop=aa)2]− and [Co(cop=aa)2]− (aa=ala−, val−, leu−, phe−), where H2(l-mop=aa) and H2(cop=aa) denote amino acid-Schiff bases of l-menthyl 3-(o-hydroxybenzoyl)propionate and cholesteryl 3-(o-hydroxybenzoyl)propionate, respectively, were prepared in solution. The intensity of the CD peak induced at 520 nm changes with the solvent used for preparation of the complex, decreasing in the order: ethanol, methanol, dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile. Since the order corresponds to the increasing order of the CH···π-interaction between the solvent and benzene, it seems that the CH···π-interaction between the chiral group and the aromatic nucleus in the ligand plays an important role in determining the configuration of the complexes.
The Reaction Process between α-Iron(III) Oxide and Sulfur Dioxide in the Presence of Carbon
Authors: Araki Hiromitsu , Ryoo Young Hong , Eguchi Motonori , Matsuzaki Ryoko , Saeki Yuzo 
Published: July 2006

Abstract
The reaction products obtained by heating a mixture of α-Fe2O3 and carbon in a SO2 stream at various temperatures were examined. The possible reactions during the above process were also examined. The solid products obtained by heating a mixture of α-Fe2O3 and carbon in a SO2 stream were Fe3O4 at 500–700 °C, pyrrhotite and Fe3O4 at 750 °C , and pyrrhotite (Fe0.88S) alone at 800 °C. Sulfur was obtained outside the heating zone throughout the temperature range. The process of the formation of pyrrhotite by the reaction between α-Fe2O3 and SO2 in the presence of carbon can be represented as follows: The reaction between carbon and SO2 occurs even at 350 °C to form sulfur, and the reaction proceeds markedly above ca. 700 °C. Above ca. 500 °C, the reductions of α-Fe2O3 with carbon and sulfur occur to form Fe3O4. Above ca. 750 °C, pyrrhotite is formed by the reaction between Fe3O4 and sulfur. These results were supported by the thermodynamical consideration based on the chemical potential diagram for the Fe–S–C–O system.
Thiocarbonyl Ylide Intermediates Generated by Deprotonation of 2-Phenacylthio- and 2-(p-Bromophenacylthio)-1,3-dithiolylium and 2-(p-Bromophenacylthio)-1,3-dithiolanylium Bromides
Authors: Nakayama Juzo , Takemasa Toshiro , Hoshino Masamatsu 
Published: July 2006

Abstract
2-(p-Bromophenacylthio)-1,3-dithiolylium bromide, when treated with triethylamine, gave 2-(p-bromophenacylidene)-1,3-dithiole (17%) and bis[(p-bromobenzoyl)(1,3-dithiol-2-ylidene)methyl] disulfide (72%). Treatment of 2-phenacylthio-1,3-dithiolylium bromide with triethylamine also gave similar results. On the other hand, 2-(p-bromophenacylthio)-1,3-dithiolanylium bromide yielded 1-(p-bromophenyl)-2-(1,3-dithiolan-2-yl)-2-thioxoethanone (12%) in addition to 2-(p-bromophenacylidene)-1,3-dithiolane (49%) contrary to the reported results. These results can best be rationalized by 1,3-cyclization of thiocarbonyl ylide intermediates to the valence tautomeric episulfides.
Photochemistry of Host–Guest Complex. III. Effect of Guest Cation on the Photoreactivity of Acetophenone Oxime Derivatives Having Crown Ether Moiety
Authors: Tada Masaru , Hirano Hideki , Suzuki Atsushi 
Published: July 2006

Abstract
The syn-anti isomerization of acetylbenzocrown ether oximes was stimulated by the complex-formation with sodium ion. The photolysis of these oximes gave mother ketones and amides through an oxaziridine intermediate. The photolysis of the oximes was depressed by the formation of host-guest complexes. Reactivity in the photolysis of the crown ether oximes corresponds to that of 3,4-dimethoxyacetophenone oxime, whereas the reactivity of the complexed crown ether oxime with sodium ion corresponds to that of p-cyanoacetophenone oxime. Such behavior is explained by the change of the electronic properties of excited states of acetophenone oxime chromophore, which enhances the intersystem crossing.
Stereochemistry of Nucleophilic Addition Reactions. 10. Preparation of 2-C-Diacetylmethyl and 2-C-Acetylmethyl Derivatives with the Altro, Gluco, and Manno Configuration from Methyl 4,6-O-Benzylidene-2,3-dideoxy-3-nitro-α-d-erythro-hex-2-enopyranoside
Authors: Sakakibara Tohru , Seta Akinori , Tachimori Yoshifusa , Sudoh Rokuro 
Published: July 2006

Abstract
Reaction of the title compound with acetylacetone in the presence of a catalytic amount of sodium hydroxide afforded the 2-C-diacetylmethyl and 2-C-acetylmethyl derivatives having the altro, gluco, and manno configurations. The 2-C-diacetylmethyl derivative with the altro configuration exceptionally exists in a skew boat form. The product ratio depends on solvent and the amount of THF.
Synthesis of dl-12,15-Ethylene-13,14-dihydro-prostaglandin-F2α Methyl Ester
Authors: Hamanaka Nobuyuki , Nakai Hisao , Kurono Masayasu 
Published: July 2006

Abstract
A report is given on the synthesis of a spiro prostaglandin analog via triketone obtained by the double Michael addition of 1,3-cyclopentanedione to 1,4-pentadien-3-one.