Nobuyuki Sugita

Use of naphthalene as a solvent for selective formation of the 1:1 diels-alder adduct of C60 with anthracene

Abstract A reaction of C 60 with an equimolar amount of anthracene in refluxing naphtlhalene gives the 1:1 Diels-Alder adduct in 67% yield based on consumed C 60 : the adduct was fully characterized by IR, UV-vis, 1 H and 13 C NMR, and MS spectroscopy, and exhibited reversible reduction waves at the potential 0.11 to 0.19 V more negative and an irreversible oxidation peak at the potential 0.11 V less positive than those of C 60 itself.

Carbonylation of aryl- and vinyl-tellurium compounds with carbon monoxide in the presence of palladium(II) salts

Abstract Aryl- and vinyl-tellurium(II or IV) compounds react with carbon monoxide (CO) in suitable organic solvents to give the corresponding carboylic acids in moderate to quantitative yields in the presence of a stoichiometric amount of a palladium(II) salt. Treatment of ( Z )-styrylphenyl telluride with atmospheric pressure of CO at room temperature in the presence of palladium(II) chloride or lithium chloropalladate(II) affords predominantly ( E )-cinnamic acid, while in the presence of palladium(II) acetate similar reaction gives the ( Z )-acid highly selectively. Under higher CO pressures (5–50 atm), however, the ( Z )-acid becomes the major product, even when palladium(II) chloride is used. The following pathways are proposed for this carbonylation: (1) in the first step organotellurium compounds form the monomeric and/or dimeric palladium complexes such as [(R 2 Te)PdCl 2 ] 2 and/or (R 2 Te) 2 PdCl 2 (R = aryl, vinyl), then (2) the migration of R moiety from tellurium to palladium (transmetallation) occurs to afford the reactive aryl- or alkenyl-palladium compounds, and (3) the compounds react with CO to give the corresponding acylpalladium compounds, after alkaline hydrolysis, the carboxylic acids are formed. The presence of an ionic carbene-like organopalladium complex is proposed for the formation of the ( Z )-acid from ( Z )-telluride.

Palladium(O)-catalyzed carbonylation of alkenyl- and aryl- borates and boronic acids with carbon monoxide

Abstract Alkenyl- and aryl-borates and boronic acids react with Co under atmospheric pressure in methanol at 25°C in the presence of a catalytic amount of Pd(PPh 3 ) 4 to give the corresponding methyl carboxylates and ketones in moderate yields.

Lifetimes of N2O+(A), CS+2(A), and CS+2(B) states produced by pulsed EUV photons

Pulsed Ne i resonance lines (73.6 and 74.4 nm) were generated by a dc discharge lamp consisting of a charging resistor, a coaxial capacitor, and a spark gap. By a single‐photon counting technique, the radiative lifetimes of N2O+(A 2Σ+, v′1=0 and 1), CS+2(A 2Πu), and CS+2(B 2Σ+u) states were measured. The Stern–Volmer treatments gave the quenching rate constants for the excited ions in the collision with the neutral parent triatomic molecules.

A new route to seleno and telluro esters by Co2(CO)8-mediated and -catalyzed carbonylation of diaryl diselenides and ditellurides with carbon monoxide

Abstract Diaryl Diselenides react with CO(5–100 atm) at 100-200°C during 1–4 h in the presence of Co2(CO)8 to give the corresponding aryl selenocarboxylic acid esters in 21–96% yields. Similar treatment of diphenyl ditelluride gives the telluro analogues in lower yields. Didodecyl diselenide also gives the corresponding seleno ester, while esters were not produced from dibenzyl diselenide and didodecyl ditelluride. Under milder conditions (10 atm CO/125°C/1 h) the reactivity of (PhM)2 (M  S, Se, Te) for the corresponding esters was found to be in the order Te > Se > S. The carbonylation of diaryl diselenides proceeds catalytically in Co2(CO)8 in the presence of triphenylphosphine. It was shown unambiguously that benzoylcobalt tetracarbonyl, which is one of the possible intermediates when aryl is phenyl, reacts smoothly with diphenyl diselenide or ditellutide to give the corresponding ester, phenyl selenobenzoate or tellurobenzoate, respectively, in a good yield.

Dominant cis-diacetoxylation of alkenes with tellurium(IV) oxide and lithium bromide in acetic acid

Summary Oxidation of alkenes with tellurium(IV) oxide and lithium bromide in acetic acid affords the corresponding α,β-diacetoxyalkanes in good yields after acetylation of the primary products with acetic anhydride/pyridine. From cyclic alkenes such as cyclopentene, cyclohexene, cycloheptene, and 1,4-cyclohexadiene, the cis-diacetate is obtained as almost the sole product. In the cases of linear cis-alkenes such as cis-2-octene and cis-4-octene cis-stereochemistry is also preferred (cis / trans = 87 ∼ 89/13 ∼ 11), while the proportion of the cis-product is decreased in the cases of the corresponding trans-alkenes (cis / trans = 56 ∼ 58/44 ∼ 42). Transformation of a C Te bond to a C OAc bond under these reaction conditions is shown unambiguously by using β-chloroalkyltellurium(IV) trichlorides (TeCl4 adducts of alkenes) and β-oxyalkyl phenyl tellurides (oxytellurenylation products of alkenes), cis-diacetates being solely formed from the trans-tellurium compounds in a cyclohexyl system. One of the possible reaction pathways for the oxidation is proposed which involves the acetoxy-, hydroxy- and/or halogeno-tellurinylation of a double bond followed by an SN2 type acetolysis of the produced C Te bond.

Vibrational relaxation of CO+(A 2Πi, v′=1) and CO+(B 2Σ+, v′=1) ions in the collision with CO molecules

The vibrationally selected CO+(A 2Πi, v′=0,1) and CO+(B 2Σ+, v′=0,1) ions were generated by the photoionization of CO using Ne and He resonance lamps, respectively. The quenching cross sections of the excited ions were found to be very large and exceed gas kinetic values in the B 2Σ+ state. In both excited states it has been observed that the vibrationally excited v′=1 ion relaxes to v′=0 level through the collision with the parent CO molecules. The branching ratio of quenching to relaxation in the v′=1 ions was explained by a cascading relaxation mechanism in which all the vibrational levels underlying the excited v′=1 level contribute to the energy transfer.

Co2(CO)8-mediated and -catalyzed carbonylation of diaryl diselenides and ditellurides to seleno and telluro esters

Abstract Diaryl diselenides and ditellurides react with CO (5–100 atm) at 100–200°C in the presence of Co2(CO)8 to give the corresponding seleno and telluro esters in 21–96% yield. The carbonylation proceeds catalytically in CO2(CO)8 in the presence of triphenylphosphine. It was shown unambiguously that benzoylcobalt tetracarbonyl, which is one of possible intermediates, reacts with diphenyl diselenide or ditelluride to give phenyl selenobenzoate or tellurobenzoate, respectively.

HIGH PRESSURE SYNTHESIS OF CYCLOADDUCT OF FULLERENE C60 WITH 2H-PYRAN-2-ONE

Abstract Under high pressure conditions, fullerene C60 smoothly reacts with 2H-pyran-2-one to give a [4+2] cycloadduct, which can be reduced to an alcohol derivative. ∗∗Presented in part at the 68th Annual Meeting of the Chemical Society of Japan held at Nagoya (October, 1994); Abstract of Papers, p. 352.

Oxidative conversion of β-hydroxyselenides to epoxides and ketones with meta-chloroperbenzoic acid

Treatment of β-hydroxy-primary-alkyl and β-hydroxy-β-phenyl-primary-alkyl selenides with 3–5 equiv. of meta-chloroperbenzoic acid in methanol or tetrahydrofuran gives the corresponding epoxides and phenyl migrated ketones, respectively, in high yields.