bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemical Reaction of (

Remark: Graphics omitted.

) with Ph2C2; Definitive Characterisation of an Insertion Product with a Seven-Membered Metallocyclic Ring
Authors: Grigsby Warren J , Main Lyndsay , Nicholson Brian K 
Published: July 2006

Abstract
The main isolated product from the photochemical reaction of (Remark: Graphics omitted.) with Ph2C2(previously characterised as a η2-acetylene adduct) is shown by an X-ray crystal structure analysis to be (Remark: Graphics omitted.) , formed by insertion of the alkyne into the Mn-C bond.[Crystals are tetragonal, space group I41⁄a, a=30.813(6) Å, c=12.647(5) Å, V=12007(6) Å3, Z=16, R=0.0793 for 1589 reflections with I&gt;3σ(I)].
The Interaction of DNA with Hoechst 33258 Studied by Fluorescence Spectroscopy
Authors: Kubota Yukio 
Published: July 2006

Abstract
The interaction of DNA with the bi-1H-benzimidazole dye Hoechst 33258 at a high molar ratio of DNA phosphate to dye has been studied by means of steady-state and nanosecond time-resolved emission spectroscopy. The spectral shifts and lifetime data, which can be interpreted in terms of the solvent-solute relaxation, are consistent with the existence of two types of bound species. One type, less hydrated bound species, predominates at high ionic strength, whereas the other, more hydrated bound species, occurs at low ionic strength.
Indirect Electrooxidation of Halohydrins by a Double Mediatory System of Ru(VIII)/Ru(IV) and [Cl+]/Cl−. Optimization for the Oxidation of 1,3-Dichloro-2-propanol to 1,3-Dichloroacetone
Authors: Torii Sigeru , Inokuchi Tsutomu , Matsumoto Sigeaki , Saeki Takeaki , Oki Tsunehei 
Published: July 2006

Abstract
Optimum conditions for the electrooxidation of 1,3-dichloro-2-propanol (1) to 1,3-dichloroacetone (2) by using a double redox system of Ru(VIII)/Ru(IV) and [Cl+]/Cl− are elucidated. The electrolysis of 1 in an AcOEt–aqueous NaCl (2:3 v/v) system buffered at pH 2–4 in a divided cell at 0–5°C gives 2 in 98% selectivity toward 1,1,3-trichloroacetone (3) under the current efficiency of 92%.
Raman Spectra and Pressure-Induced Phase Transition of Phenothiazine Crystal
Authors: Araki Gako , Mukai Mikako , Nakayama Hideyuki , Ishii Kikujiro 
Published: July 2006

Abstract
The Raman spectra of the phenothiazine crystal were measured at high pressures up to 20 kbar in a diamond-anvil cell (DAC) at several temperatures. A pressure-induced phase transition was found to occur at 2.2 kbar and 297 K. The high-pressure phase was shown to be the same as the low-temperature ferroelastic phase previously found at atmospheric pressure. The wavenumber of the fluorescence band R1 of ruby, used as the pressure monitor in DAC, was precisely measured to obtain its temperature dependence in the temperature region where the present Raman measurements were carried out.
Accurate Determination of NMR Chemical Shifts in Alkali Halides and Their Correlation with Structural Factors
Authors: Hayashi Shigenobu , Hayamizu Kikuko 
Published: July 2006

Abstract
High-resolution solid-state NMR spectra of alkali halides have been measured using the magic angle spinning (MAS) of the sample, and chemical shifts of 7Li, 23Na, 87Rb, 133Cs, 35Cl, 79Br, and 127I have been determined accurately. The 39K chemical shifts have been determined by NMR without MAS. As the ratio of the cation radius to the anion radius (Rm) increases, the chemical shifts of halogen nuclei show an upfield shift when Rm&lt;0.6, while they show a downfield shift when Rm&gt;0.6. The chemical shifts of the halogen nuclei are explained in terms of the first and the second nearest neighbor interactions, both of which cause a downfield shift. On the other hand, the chemical shifts of alkali nuclei show a downfield shift for the ratio of the anion radius to the cation radius (Rx) less than 1.6, while they show an upfield shift for Rx&gt;1.6. The chemical shifts of the alkali nuclei are expressed by the sum of the nearest neighbor interaction in the absence of the halogen-halogen interaction and the “isolation effect” caused by the halogen-halogen interaction. The “isolation effect” makes the chemical shifts approach to the values of the isolated ions.
Photooxidation of Alkylbenzenes in the Presence of Bromides
Authors: Nakada Masahiro , Fukushi Sachio , Hirota Minoru 
Published: July 2006

Abstract
In the presence of organic bromides, toluene was oxidized photochemically by molecular oxygen, producing benzaldehyde as the major product. A modified procedure using hydrobromic acid and bubbling air also gave benzaldehyde with high efficiency and can be applied for the synthetic purpose. Similarly ethylbenzene gave acetophenone.
Effect of Starting Compositions on the Growth of Calcium Tungstate Crystals from Sodium Tungstate Flux
Authors: Oishi Shuji , Hirao Minoru 
Published: July 2006

Abstract
Experimental evidence for the effect of starting compositions on the growth of CaWO4 crystals from Na2WO4 flux was given on the basis of the obtained solubility data. Crystal growth was conducted by heating mixtures at 1100°C for 5 h, followed by cooling to 500°C at a rate of 5°C h−1. Octahedral crystals up to 4.5 mm in size were grown. Mixture with ΔTSL(=TSoak temperature−TLiquidus temperature)=340°C produced 226 crystals measuring about 2.2 mm on the average. The crystal sizes decreased gradually and crystal numbers increased remarkably with a decrease in ΔTSL. The crystal sizes were mainly determined by the number of crystals grown. The value of ΔTSL played an important role in controlling the size and number of the crystals grown. It was experimentally confirmed that a greater ΔTSL or lower solute content resulted in larger crystals.
Temperature-Programmed Desorption of Dimethylpyridine Adsorbed on Silica–Alumina Prepared by Chemical Vapor Deposition
Authors: Sato Satoshi , Tokumitsu Masahiro , Sodesawa Toshiaki , Nozaki Fumio 
Published: July 2006

Abstract
A temperature-programmed desorption of adsorbed dimethylpyridine clarified the characteristic changes in acid type, acid strength, and acid amount of silica–alumina prepared by depositing silica on an alumina support. Lewis acid sites of the alumina changed into Brønsted acid sites together with a change in the acid strength with increasing silica deposition.
Photofading Reaction of Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) in the Presence of N,N′-Dimethylformamide
Authors: Enmanji Koe , Takahashi Kenzou 
Published: July 2006

Abstract
Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) was found to undergo photofading in the presence of dimethylformamide, by the action of photogenerated superoxide. Addition of a detergent suppressed the formation of superoxide, with an efficiency paralleling the fatty acid chain length.
Characteristics of Semiconductor and Ion-Sensitive Layers That Affect Response of Ion-Sensing Devices Based on n-SnO2/Ion-Exchange Membrane Junction
Authors: Kimura Keiichi , Kawasaki Yoshiaki , Yokoyama Masaaki 
Published: July 2006

Abstract
The carrier density and thickness of both the semiconductor and ion-sensing membrane were found to significantly affect the sensitivity of ion-sensing devices with a junction of n-type SnO2 and cation-selective plasticized polymeric membranes. When an anion-selective membrane was employed instead, the resulting device responded in a different way from the corresponding cation-sensing device.
Synthesis of 3- and 4-(ω-Phenylalkyl)catechols, the Sap Exuded from a Burmese Lac Tree, Melanorrhoea Usitate
Authors: Miyakoshi Tetsuo , Du Yumin , Kumanotani Ju 
Published: July 2006

Abstract
The presence of 3- and 4-(ω-phenylalkyl)catechols in Burmese lac has been confirmed by their synthesis. 3-(ω-Phenylalkyl)veratroles were synthesized by alkylation of ω-phenylalkyl bromide with aryl lithium derived from veratrole. 4-(ω-Phenylalkyl)veratroles were similarly obtained from ω-phenylalkyl bromide and 4-bromoveratrole. Demethylation of 3- and 4-(ω-phenylalkyl)veratroles with boron tribromide gave the corresponding catechols in good yields.
Crystal Structures of Polymorphic [Fe4(η5-C5H5)4S4](PF6)
Authors: Shimoi Mamoru , Satoh Asako , Ogino Hiroshi 
Published: July 2006

Abstract
[Fe4(η5-C5H5)4S4](PF6) crystals showed polymorphism depending on the recrystallization conditions. Recrystallization from acetonitrile–H2O solution gave monoclinic crystals: C2/c with lattice constants a=18.555(2), b=7.650(1), c=17.850(3) Å, β=96.81(2)°, and Z=4. Recrystallization from N,N dimethylacetamide–ether solution gave tetragonal crystals: I\bar4 with lattice constants a=12.917(2), c=7.637(1) Å, and Z=2. Molecular structures of both crystal systems are almost the same as each other, if the structure for the latter was analyzed assuming that enantiomeric cations are disordered.
Nucleophilic Displacement Catalyzed by Transition Metal. IX. [Pd2(dba)3]·CHCl3–DPPF Catalyzed Cyanation of Aryl Halides and Aryl Triflates
Authors: Takagi Kentaro , Sasaki Ken , Sakakibara Yasumasa 
Published: July 2006

Abstract
A catalyst system comprising [Pd2(dba)3]·CHCl3 and DPPF was proved to be efficient for the cyanation of aryl iodides and aryl triflates with KCN. The reactivities of aryl substrates decreased in the order ArI&gt;ArOTf&gt;ArBr.
A Novel Synthesis of Methylenecyclopropane Spiro-Linked with Cycloalkanes via a Cyclization of Allylic Epoxides and Its Application to a Synthesis of Fused 3-Methylfurans
Authors: Satoh Tsuyoshi , Kawase Yasushi , Yamakawa Koji 
Published: July 2006

Abstract
Ring closure of allylic epoxides derived from 1-chloroalkyl phenyl sulfoxides and cyclic ketones with lithium diisopropylamide (LDA) in 3-Exo-Tet mode gave spiro-linked methylenecyclopropanes having a hydroxyl group in good yields. Oxidation of these compounds gave ketones, which were then treated with p-toluenesulfonic acid in 1,4-dioxane or DMSO at 100°C to give fused 3-methylfurans in good overall yields. This procedure was applied to a synthesis of menthofuran from 4-methylcyclohexanone.
Rates and Mechanism for the Solvolyses of 2,2-Dimethyl-2-sila-1-indanyl Bromide and α-Trialkylsilylbenzyl p-Toluenesulfonates. α-Silicon Effect on the Stability of Benzylic Cations in Solution
Authors: Shimizu Nobujiro , Osajima Erika , Tsuno Yuho 
Published: July 2006

Abstract
α-Silicon effect on the benzylic solvolysis has been investigated. The solvolysis of 2,2-dimethyl-2-sila-1-indanyl bromide in aq acetone exhibits a linear response to the solvent ionizing power YBr with a slope m close to unity (m=0.93) and gives the corresponding alcohol without skeletal rearrangement indicative of a kc mechanism; it solvolyzes 4.98×102 times less rapidly than a carbon reference, 2,2-dimethyl-1-indanyl bromide, in 60% aq acetone at 25°C suggesting that solvolytic generation of the α-silylated benzylic cation is electronically about 4 kcal mol−1 less favorable than that of the corresponding α-alkylated benzylic cation. A more pronounced rate-retardation of 1.65×104 by an α-SiMe3 group relative to Me is observed in the solvolysis of an open benzylic system due to the additional steric effect. Mechanism for the solvolysis of α-trialkylsilylbenzyl p-toluenesulfonates including SiMe3, SiEt3, and Si(t-Bu)Me2 groups has been also examined on the basis of the solvent effect, salt effect, and ethanol/water selectivity as well as product analysis; a kc mechanism including a product forming step via preferential front side solvent attack is suggested.
Redox Reaction of Aromatic Aldehydes with Fe3(CO)12
Authors: Itoh Keiji , Nakanishi Saburo , Otsuji Yoshio 
Published: July 2006

Abstract
Aromatic aldehydes react with Fe3(CO)12 in refluxing benzene ultimately to give arylmethyl alcohols and 1,2-diaryl-1,2-ethanedione in a 1:1 ratio. In some cases, small amounts of 2,4,5-triaryl-1,3-dioxolanes are formed as minor products. Dinuclear iron complex (1,2-diphenyl-1,2-ethanedioxido)Fe2(CO)7 has been isolated as an intermediate in the reaction of benzaldehyde with Fe3(CO)12. The mechanism of this redox reaction of aromatic aldehydes are discussed on the basis of the kinetic study of the reaction and also of the reactivity of the isolated dinuclear iron complex.
ESR and Magnetic Susceptibility Studies on High-Spin Tetrahedral Cobalt(II)–Thiolate Complexes: An Approach to Rubredoxin-Type Active Sites
Authors: Fukui Kouichi , Ohya-Nishiguchi Hiroaki , Hirota Noboru 
Published: July 2006

Abstract
Magnetic susceptibility and ESR studies on high-spin (S=3⁄2) tetrahedral cobalt(II)–thiolate complexes were performed for A2[Co(SPh)4]; A=Me4N (1a), Et4N (1b), Ph4P (1c) and (Et4N)2[Co(SR)4]; R=C6H4-p-Me (2), C6H4-p-Cl (3), C6F5 (4). It was found that the magnitude of zero-field splitting and the anisotropy of g-factor are exceptionally large for 1c as D≈−100 cm−1, E≈0, gx≈gy&lt;gz. This parameter set shows that Co(SPh)42− in 1c is strongly affected by an axial distortion. On the contrary, a rhombic distortion with moderate magnitude was found for 1a (D*=6.5 cm−1, E⁄D=−0.21) and 1b (D*=5.0 cm−1, E⁄D=0.19). The results for the other compounds are D*=7.0 cm−1, E⁄D=0.14 for 2, D*=12 cm−1, E⁄D=0.10 for 3, and D*=2.0 cm−1, E⁄D=0.02 for 4. Attempts were made to correlate the magnetic properties and the coordination geometry for 1a–c by use of available X-ray data. As a result, the importance of the orientation of the thiolate ligands was confirmed.
1 : 1 Adduct Ion Formation of Permethylated Monosaccharides with Organic Cations in FAB Mass Spectrometry
Authors: Sawada Masami , Ouyang Li , Takai Yoshio , Yamada Hitoshi , Shizuma Motohiro , Kinoshita Takeshi , Mochizuki Tomoko , Hanafusa Terukiyo 
Published: July 2006

Abstract
The 1 : 1 adduct ion formation between a series of permethylated monosaccharides (M; Ia–Ih) and an organic or a metallic cation (A+) has been examined in quantitative FAB mass spectrometry. In a careful comparison under the same FABMS conditions, the relative (M+A)+ peak intensities increase in the following order of the monosaccharides, and further increase at nearly the same extents in spite of using three different cations such as octylammonium, (methoxycarbonyl) methylammonium, and potassium ions:
β-Glc&lt;α-Glc&lt;α-Gal&lt;β-Gal≤α-Man&lt;β-Man&lt;α-Tal&lt;β-Tal.
The order and cation-independency clearly indicate the OCH3 configurational effects of M on (M+A)+ adduct ion formation. The findings can be interpreted in terms of multisite electrostatic interaction of oxygens with the cation. Coupled with the results of gas-phase behavior by FABMS/MS(CAD), solution behavior by 1H NMR, and model calculations by MNDO, the characteristic structure of the 1 : 1 adduct ion is deduced as host-guest type association between permethylated monosaccharides and cationic species in particular cases, at least β-Tal and α-Tal cases.
Electrode Kinetics of the [Fe(CN)6]4−⁄3− Complex Confined in Cationic Perfluoropolymer Films on Electrode Surfaces
Authors: Okajima Takeyoshi , Ohsaka Takeo , Oyama Noboru 
Published: July 2006

Abstract
A heterogeneous electron-transfer process of the [Fe(CN)6]4−⁄3− complex confined electrostatically in cationic perfluoropolymer (CPFP) films on graphite electrodes and a homogeneous charge-transport process within the films were examined by potential-step methods. The relevant kinetic parameters (i.e., standard rate constant; k°/cm s−1 and transfer coefficient; α) of the heterogeneous electron-transfer process and the apparent diffusion coefficient (Dapp/cm2 s−1) of the homogeneous charge-transport process within the films were evaluated at various concentrations (C°) of the complex within the film. The values of Dapp and k° slightly decreased with an increase in C°. The value of α was independent of C° (cathodic transfer coefficient, αc=0.20, anodic transfer coefficient; αc=0.80), The values of k°, α, and Dapp were compared with those obtained previously for protonated poly(4-vinylpyridine) (PVPH+)–[Fe(CN)6]4−⁄3− system and poly(N,N-dimethylaniline) (PDMA)–[Fe(CN)6]4−⁄3− system. It was found that k°, αc, and Dapp decrease, depending on the polymer film in which the complex is confined, in the following order: for Dapp and k°, PVPH+&gt;PDMA&gt;CPFP and for αc, PVPH+≈PDMA&gt;CPFP.
On the Reaction of (Vinylimino)phosphoranes. Part 17. Preparation of N-Vinylcarbodiimides and Their [4+2] Cycloaddition with Several Dienophiles to Give Pyridine Ring System
Authors: Nitta Makoto , Soeda Hironobu , Koyama Shinya , Iino Yukio 
Published: July 2006

Abstract
The aza-Wittig reaction of (vinylimino)triphenylphosphorane and its several derivatives was examined to give N-phenyl-N′-vinylcarbodiimide and its derivatives, all of which underwent a [4+2] cycloaddition reaction with electron-rich dienophiles (enamines) and/or electron-deficient dienophiles (activated acetylenes), resulting in the formation of a pyridine ring system. The regioselectivity of the cycloaddition reaction could be rationalized on the basis of a frontier orbital consideration.
Cross-Dehydrocycloaddition of 1,3-Butadiene with Isoprene over MgO and ZrO2
Authors: Suzuka Hiroyasu , Hattori Hideshi 
Published: July 2006

Abstract
A mixture comprising of equal amounts of 1,3-butadiene (BD) and isoprene (IPN) was allowed to react over MgO and ZrO2 at 473 K in order to examine the relation between the product distribution and the reaction mechanisms. Over ZrO2 the most abundant product was 4-ethyltoluene, which was produced by a base-catalyzed Diels–Alder reaction between BD and IPN, followed by double-bond migration and dehydrogenation. In the Diels–Alder reaction, IPN acts as a diene and BD acts as a dienophile. Over MgO, o-xylene was primarily produced by anionic mechanisms. Among the products formed from BD and IPN, 4-ethyltoluene was produced most, though the production of 3-ethyltoluene was considerable. The active sites on ZrO2 were strongly poisoned by both CO2 and NH3. The active sites on MgO were completely poisoned by CO2, and were modified by NH3 in such a way that the reaction mechanisms changed from the anionic mechanisms to those involving the Diels–Alder reaction.
Mixed-Ligand Palladium(II) and Platinum(II) Complexes—Photosensitizers of 1O2 Production and Chemical Quenchers of 1O2
Authors: Kamath Shobha S , Shukla Santwana , Srivastava Tapeshwari S 
Published: July 2006

Abstract
[M(nn)(dhn)] (where M is Pd(II) or Pt(II), nn is 2,2′-bipyridine, 1,10-phenanthroline, 2,2′-biquinoline, or 4,7-diphenyl-1,10-phenanthroline, and dhn is dianion of 2,3-naphthalenediol) photooxidizes the 2,2,6,6-tetramethyl-4-piperidinol in N,N dimethylformamide via 1O2 when irradiated with light of wave-lengths of 420 to 800 nm in presence of molecular oxygen. The presence of 1O2 as an intermediate is confirmed by quenching studies using bis(dibutyldithiocarbamato)nickel(II) and 20% water in DMF. The relative efficiency of 1O2 production sensitized by the above complexes depends on nature of metal, ligand, and geometry of the complexes. However, [Pd(bpy)(dmt)] and [Pd(phen)(dmt)] undergo photooxidation via 1O2 when sensitized by hematoporphyrin IX and its metal derivatives on photolysis under similar conditions. The relative efficiency of 1O2 production depends on the nature of metal in porphyrin.
Spinning Effect on Magic-Angle-Spinning NMR Spectra of Silicone Rubber
Authors: Hayashi Shigenobu , Hayamizu Kikuko 
Published: July 2006

Abstract
High-resolution solid-state 13C, 29Si, and 1H NMR spectra of silicone rubber have been measured using the magic-angle spinning of the sample. The spectra of the three nuclei split into two or three components in the range of the spinning rate between 1.4 and 2.0 kHz. Below 1.4 kHz and above 2.0 kHz, the spectra consist of only one component. Stress caused by the fast spinning is considered to cause conformational changes in the polydimethylsiloxane chains.
Difference in Kinetic Behavior on the Photosensitized Decomposition of the Tris(oxalato)cobaltate(III) Ion by Tris(2,2′-bipyridine)ruthenium(II) and Bis(3,3′-biisoquinoline) (2,2′-bipyridine)ruthenium(II)
Authors: Kato Masako , Ohonishi Yuki , Kimura Masaru 
Published: July 2006

Abstract
The photo-sensitized decomposition of [Co(ox)3]3− (ox=oxalate) was performed using [Ru(bpy)3]2+ (bpy=2,2′-bipyridine) and [Ru(i-biq)2(bpy)]2+ (i-biq=3,3′-biisoquinoline). The dramatic difference in the decomposition behavior appeared between them. In appearance, the decomposition rate obeys first-order with respect to the [Co(ox)3]3− concentration for [Ru(i-biq)2(bpy)]2+ system, whereas zero-order for the [Ru(bpy)3]2+ system. The cause was discussed on the basis of the kinetic analysis.
Fluorogenic Substrate of Pepsin
Authors: Yonezawa Hiroo , Izumiya Nobuo 
Published: July 2006

Abstract
Fluorogenic substrates of pepsin; Dns–Ala–Phe–Trp–Val–Leu–OCH2Py and Dns–Phe–Trp–Val–Leu-OCH2Py were synthesized by a solution method. Incubation of pepsin with Dns–Ala–Phe–Trp–Val–Leu–OCH2Py resulted in specific cleavage at the Phe–Trp bond and the time-dependent increase in fluorescence intensity at 345 nm paralleling the extent of substrate hydrolysis. The optimum pH of the substrate was 3.0 and the Km and kcat values were 8.0×10−5 M and 0.10 s−1, respectively. The linearity of the plot of fluorescence intensity vs. enzyme concentration was satisfactory in the range of 50 nM to 500 nM of pepsin at a substrate concentration of 50 μM. Because of its simplicity and rapidity, this method is useful for the measurement of pepsin action. In contrast, Dns–Phe–Trp–Val–Leu–OCH2Py was not cleaved by pepsin.
Reinvestigation of the Phosphazo Method and Synthesis of N-(t-Butoxycarbonyl)-l-arginine p-Nitroanilide and a Chromogenic Enzyme Substrate for the Factor Xa
Authors: Oyamada Hidekazu , Saito Takashi , Inaba Shinsaku , Ueki Masaaki 
Published: July 2006

Abstract
Reaction conditions for the phosphazo method were reinvestigated in order to apply this method to the synthesis of p-nitroanilide(pNA)s of t-butoxycarbonyl(Boc)-and benzyloxycarbonyl(Z)-amino acids.
Palladium Catalyzed Reaction of Silacyclobutanes with Acetylenes
Authors: Takeyama Yoshihiro , Nozaki Kyoko , Matsumoto Kozo , Oshima Koichiro , Utimoto Kiitiro 
Published: July 2006

Abstract
Whereas the reaction of 1,1-dimethyl-1-silacyclobutane (1a) with dimethyl acetylenedicarboxylate in the presence of Pd catalyst provides dimethyl 1,1-dimethyl-1-sila-2-cyclohexene-2,3-dicarboxylate almost exclusively, the reaction of 1a with phenylacetylene affords allyldimethylstyrylsilane as a major product. The reaction of silacyclobutane with phenylallene provided three isomeric products.
Enantio- and Diastereo-Selective Synthesis of (+)-Grandisol
Authors: Narasaka Koichi , Kusama Hiroyuki , Hayashi Yujiro 
Published: July 2006

Abstract
(+)-Grandisol, an insect pheromone having cyclobutane skeleton, is synthesized enantio- and diastereo-selectively. The key steps in the synthesis are the asymmetric [2+2] cycloaddition reaction catalyzed by a chiral titanium reagent and the diastereoselective conjugate addition reaction by the combined use of Me2CuLi and trimethylsilyl trifluoromethanesulfonate.
An Useful Synthetic Method for 3-Substituted δ-Lactones. Synthesis of (±)-Secocrispiolide
Authors: Kato Michiharu , Ouchi Akihiko , Yoshikoshi Akira 
Published: July 2006

Abstract
2-Phenylthio-2-penten-5-olide (1) acted as a reactive Michael acceptor toward some typical carbon neucleophiles to give 3-substituted 2-phenylthio-5-pentanolides (2) which were convertible both to 3-substituted 5-pentanolides by reductive desulfurization and to 3-substituted 2-penten-5-olides by sulfenic acid syn elimination of the sulfoxides 4 derived from 2. The Pummerer rearrangement of 4 provided 3-substituted 2-phenylthio-2-penten-5-olides and/or 2-hydroxy-2-penten-5-olides. (±)-Secocrispiolide was synthesized via the adduct obtained by the Michael reaction of 1 with the Grignard reagent prepared from 2,6-dimethylbenzyl bromide and magnesium.