bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Synthesis and Diels–Alder Reactions of 2-Aminomethyl-1,3-butadienes and Related 1,3-Dienes
Authors: Hosomi Akira , Masunari Toshiyuki , Tominaga Yoshinori , Hojo Makoto 
Published: July 2006

Abstract
2-Aminomethyl-1,3-butadienes and 2,3-bis(aminomethyl)-1,3-butadienes, readily prepared by the Grignard cross-coupling reaction of 2-bromo-2-aminopropene and vinylic bromides, are good Diels–Alder dienes toward various activated dienophiles to afford aminomethyl-substituted cyclohexenes.
Optical Resolution by Replacing Crystallization of Ammonium Salts of N-Acetyl-Dl-2-aminobutanoic Acid, N-Acetyl-Dl-norvaline, and N-Acetyl-Dl-norleucine
Authors: Shiraiwa Tadashi , Yamauchi Masahiro , Yamauchi Takatoshi , Yamane Takao , Nagata Makoto , Kurokawa Hidemoto 
Published: July 2006

Abstract
Ammonium salts of N-acetyl-Dl-2-aminobutanoic acid, N-acetyl-Dl-norvaline (Dl-AcNva·AM salt), and N-acetyl-Dl-norleucine were optically resolved by replacing crystallization in the presence of the ammonium salt of N-acetyl-l-alanine to give their salts with l-configuration. The optical resolution of the Dl-AcNva·AM salt, espcially, gave the optically pure l-AcNva4·AM salt by purification in 80% yield based on the half amount of the Dl-salt used as the starting material.
Reactions of Benzocyclopropene with Sulfonyl Isocyanates and Nitrones: Cycloadditions through C–C σ-Bond Rupture of Three-Membered Ring
Authors: Kagabu Shinzo , Saito Katsuhiro , Watanabe Hiroyuki , Takahashi Kensuke , Wada Katsuaki 
Published: July 2006

Abstract
Alkane- and arenesulfonyl isocyanates were added to benzocyclopropene across the C–C σ-bond of the three-membered ring, giving 2-sulfonyl-1-isoindolinones. The reaction with C,N-diphenylnitrone afforded a similar cyclization product, 3,4-dihydro-3,4-diphenyl-1H-2,3-benzoxazine. These reactions are considered to proceed through zwitterionic intermediates formed by the fission of the C–C σ-bond of the three-membered ring by the electrophiles.
Oxidation of Cycloalkanes in a Radiofrequency Plasma
Authors: Tezuka Meguru , Yajima Tatsuhiko 
Published: July 2006

Abstract
Cyclopentane, cyclohexane, cycloheptane, and cyclooctane were reacted in a radiofrequency plasma containing oxygen to give mixtures of the corresponding cycloalkanones and cycloalkanols. Tetralin was also oxidized to 1-tetralone and 1-tetralol. Based on the effects of reaction variables on the oxidation rate, the reaction scheme involving the autoxidation of cycloalkyl radicals was proposed.
Vinyl Polymers Bearing Pyrrole Ring: I. Syntheses of Pyrroles Having 3-Substituent Bearing Vinyl Group
Authors: Kamogawa Hiroyoshi , Nakata Takuharu , Ohori Shin , Komatsu Sei 
Published: July 2006

Abstract
Pyrroles having 3-substituent bearing the vinyl group with an ester or amide spacer were synthesized starting with 1-(phenylsulfonyl)pyrrole. Homopolymerization of the vinyl monomers thus synthesized provided cross-linked insoluble polymers, but their copolymers with 1-vinyl-2-pyrrolidone were soluble in common solvents.
The Photosensitized Oxygenation of Furanoeremophilanes. III. The Transformations to the Skeletally Isomeric Lactones from Furanofukinol
Authors: Naya Keizo , Shimizu Mitsuaki , Nishio Hideki , Takeda Motonori , Oka Shogo , Hirota Keiji 
Published: July 2006

Abstract
Pairs of the skeletal isomers of eremophilane-type lactones were synthesized from furanofukinol via photosensitized oxygenation, followed by lactone cleavage and reformation. Their stereochemistry has been clarified so as to be consistent with a classification method outlined in our earlier papers.
Syntheses and Properties of N-Fluoropyridinium Salts
Authors: Umemoto Teruo , Harasawa Kikuko , Tomizawa Ginjiro , Kawada Kosuke , Tomita Kyoichi 
Published: July 2006

Abstract
Various stable N-fluoropyridinium salts with a non- or weakly nucleophilic counter anion such as TfO−, FSO3−, BF4−, SbF6−, ClO4−, CH3SO3− etc., or with an electron-donating or -withdrawing substituent(s) on the pyridine ring were synthesized and their properties investigated. N-Fluoropyridinium-2-sulfonates, N-fluoroquinolinium triflate, and highly hindered N-fluoro-2,6-di-t-butylpyridinium salts were also synthesized. They were synthesized by counter anion displacement reactions of unstable pyridine-F2 compounds, fluorination of salts of pyridines with protonic acids or silyl esters with F2, and/ or fluorination of Lewis acid complexes of pyridines. The scope of each method was examined in detail. Each of the N-fluoropyridinium salts was assigned as the first stable 1 : 1 salt structure of the pyridine nucleus and halogen atom on the basis of the spectral and elemental analyses. The stability depended on the nucleophilicity or basicity of the counter anions and electronic nature or position of the ring substituents. These results and NMR analyses clearly showed the unstable pyridine-F2 compounds to have N-fluoropyridinium fluoride salt structure. Some N-fluoropyridinium triflates were hydrolyzed and the products were examined, suggesting a unique hydrolysis mechanism.
Preparation, Stability, and Compositions of the Crystals of Reduced Riboflavins
Authors: Ebitani Matsue , Kashiwagi Hiroshi , Inoue Masami , Nishibe Keiichi 
Published: July 2006

Abstract
Green crystals were obtained after a reduction of riboflavin (RF) with Na2S2O4. These crystals were gradually oxidized to RF when stored in air, even at −10°C. The emission spectra and X-ray powder diffraction analyses of the green crystals clearly showed different patterns from those of RF. The ESR spectra and number of the reduced species determined by the titration with KMnO4 supported the formation of an RF-flavosemiquinone radical (1 : 1) complex. Reduced riboflavin tetrabutyrate prepared according to the same procedure was too unstable for dioxygen to obtain spectroscopic data.
Reactions of α,β-Unsaturated Ketone Acetals with Trimethylsilyl Cyanide and Trimethylsilyl Sulfides
Authors: Soga Tsunehiko , Takenoshita Haruhiro , Yamada Masaaki , Han Jeng S , Mukaiyama Teruaki 
Published: July 2006

Abstract
In the presence of a catalytic amount of trityl perchlorate, trimethylsilyl cyanide reacts with the dimethyl acetals of chalcone derivatives, with simultaneous double bond isomerization, to yield γ-methoxy-α,β-unsaturated carbonitriles. Trimethylsilyl sulfides react with dimethyl acetals derived from α,β-unsaturated ketones to yield 1,3-bis(alkylthio)propene derivatives under similar conditions.
Oxygen Effect on Photocatalytic Reaction of Ethanol over Some Titanium Dioxide Photocatalysts
Authors: Iseda Kozo 
Published: July 2006

Abstract
The suspensions of four kinds of TiO2 photocatalysts in ethanol have been studied under ultraviolet light in an atmosphere of Ar, air, or O2 at 25°C. The main products were acetaldehyde, acetaldehyde diethyl acetal (acetal), acetic acid, water, ethylene, methane, carbon dioxide, and hydrogen. Acetaldehyde and acetal were abundantly produced in all of the products. The formation of all of the products under O2 was more efficient than those under Ar and air. The photochemical activity of each TiO2 is stronger than that of either Ti2O3 or TiO.
Redox Potential of Fe4S4 Cluster in Hydrophobic and Hydrophilic Spheres
Authors: Tanaka Koji , Tanaka Satoshi 
Published: July 2006

Abstract
The redox behavior of the [Fe4S4(SC6H4But(p-))4]2−⁄3− couple was examined not only in a CH2Cl2 solution of a CH2Cl2/H2O two phase system but also in the absence and presence of Triton X-100 in H2O to elucidate the solvent effect of water on the redox potential of the cluster. Protonation of [Fe4S4(SC6H4But(p-))4]3− takes place in those media, and protonated and unprotonated clusters exist as an equilibrium mixture. Although the redox potential of the cluster is hardly affected by the pKa value, it is largely influenced by a thickness of [Fe4S4(SC6H4But(p-))4]2− adsorbed on a surface of an electrode in water. The E1⁄2 value of the cluster in a near monomolecular layer on the electrode exhibits a pronounced anodic shift compared with that in CH2Cl2 and falls in the range of that of 4Fe- and 8Fe-ferredoxins. On the other hand, the cluster in the multimolecular layer does not show such an anodic shift of the E1⁄2 value in water.
Solvation and Ionic Association of (1R,4S,8R,11S)-1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) Perchlorate in Mixed Solvents of N,N-Dimethylformamide and N,N-Dimethylacetamide with Nitrobenzene and 1,2-Dichloroethane
Authors: Yokoyama Takashi , Iwamoto Etsuro , Kumamaru Takahiro 
Published: July 2006

Abstract
The conductances of [NiL]2+ ([NiL]2+=(1R,4S,8R,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II)) have been measured in N,N-dimethylformamide (DMF)–1,2-dichloroethane (DCE), and N,N-dimethylacetamide (DMA)–DCE, and iso-relative permittivity mixtures DMF–nitrobenzene (NB), DMA–NB, and DMF–DMA at 25°C. The first ionic association constant of [NiL]2+ with the perchlorate ion in the mixtures with NB decreases with increasing fraction of both DMF and DMA, although DMF is coordinated to [NiL]2+ and DMA is not, this showing that DMA as well as DMF in NB selectively solvates the axial coordination site of [NiL]2+ to change from contact ion pairs to solvent-separated ion pairs. Bulky and delocalized negative pole of NB of which the dipole moment is larger than that of DMF and DMA results in a weak ion–dipole interaction, leading to a larger degree of ionic association. Ionic association was discussed from the viewpoint of steric hindrance and ion–dipole interactions.
Synthesis of Strapped, Dimeric, and Trimeric Porphyrins Based on Intramolecular Macrocyclization Reactions
Authors: Osuka Atsuhiro , Kobayashi Fumikazu , Maruyama Kazuhiro 
Published: July 2006

Abstract
Strapped porphyrins were prepared directly by the acid-catalyzed condensation reaction of 3,3′-diethyl-4,4′-dimethyl-2,2′-dipyrrylmethane and methylenedioxy bridged dialdehydes having a strap linkage longer than 7 atoms. Dimeric and trimeric porphyrins with coplanar and orthogonal (T-shape) geometries were also synthesized in good yields as an application of this method. In the strapped porphyrins, the distortion of porphyrin ring increases systematically on shortening the strap linkage, which is confirmed by their 1H NMR data, red shifted absorption, and fluorescence spectra. In the coplanar dimeric and trimeric porphyrins, the electronic interactions between the porphyrins were distinctly observed, while in the orthogonal “T-shaped” dimers and “H-shaped” trimers, appreciable electronic interactions were not observed.
Polymerization Mechanism of Styrene Initiated by 2,2-Bis(t-butyldioxy)alkanes
Authors: Watanabe Yasumasa , Ishigaki Hideyo , Okada Hiroshi , Suyama Shuji 
Published: July 2006

Abstract
The radical polymerization mechanism of styrene initiated by 2,2-bis(t-butyldioxy)alkanes (1) has been studied in benzene. The decomposition products of 1 are acetone, alkyl methyl ketone, t-butyl alcohol, and t-butyl peracetate. Styrene monomer converts to polystyrene along with styrene oxide. The peroxides 1 cleave homolytically at one of dioxy bonds to yield intermediate alkoxyl radicals with α-t-butyldioxyl group, which undergo β-scission to afford t-butyldioxyl or alkyl radicals. The resulting t-butyldioxyl radical reacts with styrene to form 2-(t-butyldioxy)-l-phenylethyl radical, which decomposes subsequently to styrene oxide and t-butoxyl radical via γ-scission. Alternatively, a part of t-butyldioxyl radical adds to styrene to afford polystyrene containing dioxy bond.
Effect of a Hydrogen Pretreatment on the Mechanism of Deuterium Addition and Exchange of Propene over Ni–Cu Alloy Catalysts
Authors: Naito Shuichi , Tanimoto Mitsutoshi 
Published: July 2006

Abstract
The effects of a hydrogen pretreatment on the activity and reaction intermediate in a C3H6–D2 reaction over a Ni–Cu alloy as well as Ni metal catalysts were investigated in detail by applying an isotope tracer technique. Ni metal and Ni-rich alloy catalysts, cooled down to the reaction temperature under a hydrogen atmosphere (D-surface), exhibited low activity compared to that of a surface evacuated before cooling (E-surface). For Cu-rich alloy catalysts, however, the E-surface exhibited a lower activity and a higher activation energy than did the D-surface. A comparison of the TPD spectra of adsorbed hydrogen with the dependence of the activity upon the evacuation temperature suggests that strongly adsorbed hydrogen retards the reaction over Ni and Ni-rich alloy catalysts at lower temperature. Microwave spectroscopic analysis demonstrated that the reaction intermediates over D- and E-surfaces of Cu-rich alloy catalysts were similar to those over Cu and Ni metals, respectively. This result suggests that a hydrogen pretreatment of Cu-rich alloys forms a specific surface structure which is destroyed by evacuation at elevated temperatures.
Small-Angle X-Ray Scattering Study on Sol–Gel Transition of Mixtures of Colloidal Silica and Organic Polymer
Authors: Matsuoka Hideki , Chen Sheng-rong , Ishii Hiroshi , Ise Norio , Nakanishi Kazuki , Soga Naohiro 
Published: July 2006

Abstract
Sol–gel transition of mixtures of colloidal silica–water soluble organic polymer (sodium polystyrenesulfonate) has been investigated by the small-angle X-ray scattering technique. With proceeding gelation, an increase of the intensity at small-angle regions was observed and the values of radius of gyration (Rg) were estimated by the Guinier method. The addition of polymer increased the initial increase of Rg with gelation, i.e., sol–gel transition was accelerated by the presence of the polymer. This observation is not in contradiction to the prediction of micro-phase separation into silica-rich phase and polymer-rich phase proposed by Nakanishi and Soga. The fractal analyses predicted that the geometrical structure of the gel finally formed is similar to those of random coil linear polymer and swollen branched polymer.
Mössbauer Emission Study of Recoil 119Sb and 119mTe Atoms after Nuclear Decays and Reactions in SnS and SnSe
Authors: Ambe Shizuko , Ambe Fumitoshi 
Published: July 2006

Abstract
The chemical fates of 119Sb and 119mTe recoil atoms after p- and α-reactions in SnS and SnSe were studied by Mössbauer emission spectroscopy. The 120SnS and 120SnSe samples irradiated with protons gave a partly resolved asymmetric doublet ascribable to 119Sn at the Sn site of the matrices. The α-irradiated 117SnS and 117SnSe samples gave emission spectra, drastically different from those of p-irradiated 120SnS and 120SnSe as well as that of α-irradiated 120SnTe. The spectra are decomposable into three lines which are hardly assignable to any known chemical species of Sn and S or Se. Two of the lines are assigned to a doublet of divalent 119Sn in the Sn site of SnS or SnSe with a nearby defect on the basis of their behavior on thermal annealing. The other line is ascribed to tetravalent 119Sn in a defect structure.
Dynamical Characterization in Aqueous Solutions of 3-Methoxy-and 3-Ethoxy-1-propanol by Ultrasonic Methods
Authors: Nishikawa Sadakatsu , Ueda Masayuki 
Published: July 2006

Abstract
3-Methoxy-1-propanol and 3-ethoxy-1-propanol were synthesized through potassium propoxide from 1,3-propanediol. Ultrasonic absorptions in their aqueous solutions were measured in the frequency range from 8.5 to 220 MHz as functions of their concentrations along with the sound velocity and density. In a solution of 3-ethoxy-1-propanol, a single relaxational absorption was observed; the cause was attributed to a perturbation of an equilibrium as AB ↔ A + B, where AB represents the solute-solvent complex, A the solute and B the solvent molecules. On the other hand, no relaxational absorption was observed in a 3-methoxy-1-propanol solution up to 4 mol dm−3. The thermodynamic and the kinetic parameters were evaluated for the above-mentioned process from the concentration dependences of the ultrasonic parameters in a 3-ethoxy-1-propanol solution. From evidence concerning the appearance and disappearance of ultrasonic relaxational absorption and comparisons of the rate and thermodynamic constants in aqueous solutions of various alcohols, the alternation of the water structure affected by the addition of the solutes is discussed in connection with the solute structures. The methoxyl group was explicitly found to act as a water structure breaker and the ethoxyl group to do so slightly.
Acidic Property of Rh and Ru Complexes
Authors: Kou Yuan , Yamada Nobuo , Akutagawa Susumu , Zhang Geng , Tanabe Kozo 
Published: July 2006

Abstract
The acidic property of [Rh(nbd)(dppb)]ClO4, [Ru(binap)](BF4)2, and [Ru(dmso)6](ClO4)2 was measured by using the acetalization of cyclohexanone as a test reaction and the temperature-programmed desorption [TPD] of pyridine. The acid strengths were estimated to be H0=−2.1 for [Ru(dmso)6](ClO4)2 and H0=−2.2 for [Ru(binap)](BF4)2 and [Rh(nbd)(dppb)]ClO4 by the test reaction method. The TPD method gave consistent results.
Synthesis and Properties of High Molecular Weight Polypeptides Containing of Tryptophan
Authors: Iizuka Yasuko , Endo Toshiya , Oya Masanao 
Published: July 2006

Abstract
High purity N-carboxy-Dl-tryptophan anhydride (Dl-4-indoylmethyl-2,5-oxazolidinedione, Dl-Trp NCA) was synthesized in good yield. Copolypeptides with a random sequence of Dl-Trp with l-alanine (Ala) and Dl-alanine (Dl-Ala) were synthesized by copolymerization of the corresponding N-carboxy-α-amino acid anhydrides (NCA) in solution. Copolypeptides of Dl-Trp with l-Ala and Dl-Ala were partially soluble in water. The water-soluble copolypeptides of Dl-Trp and l-Ala mostly gave disordered conformations, while the water-insoluble copolypeptides were found in a mixture of α- and disordered conformations. The solubility of the copolypeptides was not influence by the tryptophan content in the polypeptides but, rather, by the conformation of the polypeptides.
Formation of Small Cobalt Clusters from CoNaY by Reduction with H2 and Consecutive H2–O2 Treatments
Authors: Kim Jae C , Woo Seong I 
Published: July 2006

Abstract
In order to raise the degree of reduction and promote the formation of zerovalent cobalt clusters, repetitive treatments of CoNaY with hydrogen and oxygen were carried out. The intensity of FMR (ferromagnetic resonance) band of CoNaY reduced for 36 h at 773 K with intermittent oxygen treatments was twice as much as that of CoNaY reduced only with hydrogen. This fact meant that reduction of CoNaY with H2–O2 treatments favored to produce zerovalent cluster due to the increase in the mobility of Co2+ ions in CoNaY. The size of clusters is so small that such conventional methods as hydrogen chemisorption, X-ray diffraction, and TEM can not detect the quantity of zerovalent cobalt clusters. FMR spectroscopy, H2-consumption measurement, and catalytic probe reaction method were used to measure the degree of reduction and were correlated well with one another.
Reaction between Nitrogen Monoxide and Carbon Monoxide over Superconducting Bi–Sr–Ca–Cu and Related Mixed Oxides
Authors: Mizuno Noritaka , Toyama Hisashi , Tanaka Mika , Yamato Mika , Misono Makoto 
Published: July 2006

Abstract
Bi–Sr–Ca–Cu–O mixed oxides having a Bi2Sr2CaCu2Oy structure were very active for reactions between nitrogen monoxide and carbon monoxide among the prepared catalysts having perovskite and related structures.
Cobalt(IV) Amine Complexes with Organic Ligands. XI. The Preparation and Properties of Tetraammine(7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato)cobalt(IV) Complexes and the Corresponding Cobalt(III) Complexes
Authors: Yamamoto Yoshihisa , Toyota Eiko , Konno Hidetaka 
Published: July 2006

Abstract
Tetraammine(7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato)cobalt(IV) complexes and the corresponding cobalt(III) complexes have been isolated, and characterized by analytical, spectroscopic, magnetic, and XPS methods. The effective magnetic moments of cobalt(IV) complexes were ca. 1.6 BM, suggesting an unpaired spin. An unpaired spin on the complex is located over the π-orbitals of the 7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato ligand (abbreviation: chelated ligand) and on the cobalt atom from the results of the C 1s and Co 2p spectra by XPS. The Cl 2p binding energy of the chloride ion suggests that the valence electrons of the chloride ions may have some interaction with the π-orbitals of the chelated ligand.
Cyclotriveratrylene Crown Ethers: Metal Ion Extraction and Transport Abilities through Organic Membrane
Authors: Akabori Sadatoshi , Takeda Masakazu , Kawakami Hiroshi 
Published: July 2006

Abstract
Extraction abilities of cyclotriveratrylene crown ethers (2) toward alkali, alkaline earth, and other metal ions were examined. Transport of metal ions by 2 through a liquid membrane was also examined.
Preparative Derivatization of endo-Dicyclopentadiene via Metallation
Authors: Kumagai Takashi , Aga Michihiro , Okada Keiji , Oda Masaji 
Published: July 2006

Abstract
endo-Dicyclopentadiene has been selectively metallated with the base complex BuLi·t-BuOK in hexane at the olefinic positions in the norbornene moiety and a number of derivatives prepared by reaction of the metallated intermediate with electrophilic reagents. In particular, bromodicyclopentadiene thus obtained is a useful stock precursor for lithiodicyclopentadiene.
The Reaction between Hydrogen Spiro-Borates and Carbinol Form of Crystal Violet in Toluene with Applications to Reagent Selection in Extraction-Spectrophotometry of Boron
Authors: Sengupta Susanta K , Balasubramanian O 
Published: July 2006

Abstract
A study on equilibrium and kinetics of the reactions of boron complexes of a judiciously chosen series of hydroxy and dicarboxy acids (benzilic acid, mandelic acid, 3-chloro- and 4-hydroxy mandelic acid, salicylic acid, and phenylmalonic acid) as well as of the free acids with carbinol form of crystal violet in toluene demonstrated the distinct superiority of mandelic acid over the others, as a reagent for extraction-photometry of boron.
Synthesis of Tribromoacetic Anhydride and Its Reaction with Dimethyltin(IV) Oxide
Authors: Parkash Ram , Meena Meena , Singh Sukhjinder 
Published: July 2006

Abstract
The synthesis of previously unknown tribromoacetic anhydride and its reaction with dimethyltin(IV) oxide is reported. The compounds were characterized by analytical methods, IR, 1H, 13C, 119Sn NMR, and MS (EI) spectral studies.
Preferential Incorporation of a Cyclopropyl σ Bond Over an Ethylenic π Bond in the TCNE Cycloaddition of 1,2-Dicyclopropylethylene. Occurrence of the Type-II Reaction in Some Disubstituted Substrates
Authors: Nishida Shinya , Masui Masakazu , Murakami Masashi , Imai Toshiro , Tsuji Takashi 
Published: July 2006

Abstract
Among the two types of cycloadditions known to take place in the reactions of cyclopropyl-substituted ethylenes (1) with tetracyanoethylene (TCNE) (type-1 gives a cyclobutane derivative (2) and type-II yields a vinylcyclopentane derivative (3), the type-II reaction has been practically limited to occur in reactions of tetrasubstituted substrates. However, some disubstituted substrates, namely cis- and trans-1,2-dicyclopropylethylene (4 and 5), were found to produce a mixture of 2 (R1=R2 or R3=H, R2 or R3=cyclo-Pr) and 3 (R1=R2 or R3=H, R2 or R3=cyclo-Pr). In acetonitrile at 80°C, 2 predominated in the reactions of both 4 and 5, but 3 became the major adduct in 1,2-dichloroethane or benzene. The other 1,2-disubstituted ethylenes, such as 1-cyclopropylpropene, 1-cyclopropyl-3-methyl-1-butene and 1-cyclopropyl-3,3-dimethyl-1-butene, produced a small amount of 3 in solvents of low polarity; the type-II, however, has never become a major process. Parent vinylcyclopropane failed to give the type-II adduct in all of the solvents examined. Participation of the cyclopropyl σ bond in the reaction with TCNE is thus shown to have a scope wider than that presumed previously; hence, both the type-I and the type-II processes may be the two principal modes of the reaction of 1 with TCNE.