Taeko Izumi

Synthesis and electrochemical studies of ferrocene-dithiafulvalenes (Fc-DTF) and 1,1′-bis(dithiafulvalenyl)ferrocene (DTF-Fc-DTF). An approach towards new conducting organic materials

Abstract Novel π-conjugated donor compounds based on the strong electron-donating ferrocene moiety and dithiafulvalene donors exhibited increased electron donor ability. The ferrocenylketones 4a,b , 5 , 8 and 9 were synthesized via described methods, and allowed to react with 2-dimethoxyphosphinyl-1,3-benzodithiole ( 13 ) in the presence of n-BuLi at −78°C in dry THF to afford the corresponding ferrocene-dithiafulvalenes 14a,b , 18 , 19 and 1,1′-bis(benzo-1,3-dithiol-2-ylidene)ethyl]ferrocene ( 15 ). Electrochemical properties of these new donor compounds were studied using cyclic voltammetry (CV) and UV–Vis spectra. CV and absorption spectra of the new compounds were studied in comparison with ferrocene ( 6 ) and dibenzo-tetrathiafulvalene DB-TTF 3 . Two-electron and three-electron redox behaviors were observed as two waves. The absorption spectra showed a red-shift with a slight increase in the absorption intensities.

Kinetic resolution of 1,1'-binaphthylamines via lipase-catalyzed amidation

Abstract Lipase-catalyzed amidation of 2-(2-aminoethyl)-1,1′-binaphthyl (±)- 3 gave optically active 2-[2-(acylamino)ethyl]-1,1′-binaphthyls ( R )- 6a – c with high enantiomeric excess.

Design and synthesis of new functional compounds related to ferrocene bearing heterocyclic moieties: A new approach towards electron donor organic materials

Abstract The synthesis of heterocyclic systems incorporating more than one ferrocene unit was shown to be a facile and convenient route for the synthesis of new ferrocene-heterocycles. Hydrazide 2 was prepared and cyclized to oxadiazole, triazole, and pyrazole using the procedures described in this context with good yields. A pyrazolone derivative could not be obtained and instead a hydrazone derivative 17 was isolated. Hydrazide 2 was condensed with aromatic aldehydes and ferrocene-1,1′-dicarbaldehyde derivatives to give the corresponding hydrazones 11a – c and dihydrazones 12 , 14 and 18 in high yields. Cyclic voltammetry (CV) of the selected ferrocene-heterocycles 8 and 9 was studied comparing with the parent ferrocene and acetylferrocene. The CV of the compound 8 revealed an additional, quasireversible, one-electron oxidation wave at 849 mV, corresponding to the second ferrocene unit connected to the oxadiazole ring through the SCH 2 CO spacer.

Synthesis of New Functionalized Compounds Related to p-Extended Tetrathiafulvalenes with Quinonoidal Structures Bearing a Ferrocene Moiety

Summary. A number of π-extended conjugated tetrathiafulvalene (TTF) analogues were synthesized as new π-donors, and their structures and physical properties were determined. UV/Vis spectra and cyclic voltammetry of the π-extended ferrocenyl donors were studied in comparison with ferrocene, ferrocenylquinone, and the parent donor. A three-electron redox behaviour was observed. The absorption spectrum of the new donor 16 showed a slight red-shift and a slight increase in intensity relative to the compared compounds.

Synthesis of [2]paracyclo[2]paracyclo[2] (1,1') ferrocenophane derivatives.

[2]Paracyclo[2]paracyclo[2](1,1′)ferrocenophane derivatives having olefinic or acetylenic bonds and aromatic rings were synthesized by intramolecularly titanium-induced reductive coupling of carbonyl compounds. The transannular π-electronic interactions between two olefinic or acetylenic bonds and two benzene rings were examined on the basis of electronic spectra.

Effect of the alkyl chain length of 1,1′-binaphthyl esters in lipase-catalyzed amidation

Lipase-catalyzed amidation of 2-[2-(ethoxycarbonyl)ethyl]-1,1′-binaphthyl [(±)-3] yielded optically active (S)-3 and 2-[2-(2-cyanoethylaminocarbonyl)ethyl]-1,1′-binaphthyl [(R)-6a] with high enantiomeric excess. For these lipase-catalyzed amidations, the optimal alkyl chain length between the binaphthyl ring and the ester group was determined to be an ethylene spacer.

Ruthenium-catalyzed coupling reaction of benzylic halides

Abstract Reported herein is a novel method on dechlorination coupling reaction of halides by using RuCl2(PPh3)3 catalyst under a hydrogen atmosphere with benzene as the solvent, which affords alkanes in excellent yields.

Synthesis and electrochemical properties of 1,1'-bis(benzo-1,3-dithiol-2-ylidene)ferrocene derivatives as novel electron donor compounds

Abstract A number of 1,1′-bis(benzo-1,3-dithiol-2-ylidene)ferrocene derivatives 7a–b and 12–14 based on the strong electron donating ability of 1,3-dithiole and ferrocene moieties were synthesized as new π-donors. The structure and physical properties of these compounds were characterized both by experimental techniques and spectral analysis. These new classes of donor compounds were obtained in very high yields based on modification of the Wittig–Horner reaction and the 1,3-dithiole rings were separated by conjugated spacers including aryl–ferrocenyl–aryl. The electrochemical properties of the new compounds have been studied in comparison to DB-TTF 4 analogues, and the parent ferrocene donor by cyclic voltammetry (CV), using Pt electrode as the working electrode in CH2Cl2 solutions at room temperature. Three subsequent oxidation processes are observed as three oxidation waves associated only with two reduction processes. Polycrystalline samples of 14a–b are conducting σrt 14a=0.2 S cm−1 and σrt 14b=4.8×10−4 S cm−1) respectively, while compounds 15 and 16 were found essentially as insulator (σrt

Chemoenzymic synthesis of optically active 3‐methyl‐ and 3‐butylphthalides

Optically active (S)-3-methylphthalide was synthesized by the enzymic reduction of 2-iodoacetophenone using bakers yeast, followed by palladium-catalysed carbonylation under carbon monoxide. With enzymic reduction using bakers yeast, however, 2-bromo- or 2-iodovarelophenones were not reduced, even after 25 days. On the other hand, the enantioselective hydrolysis of α-alkylated 2-halobenzyl acylates using pig liver esterase, horse liver esterase or lipase from Candida rugosa resulted in the formation of (R)-α-alkylated 2-halobenzyl alcohol and (S)-acylate, and the following palladium-catalysed carbonylation of the products yielded the (R)- and (S)-3-alkylated phthalides, respectively.

Baker's yeast reduction of α-(alkoxycarbonylamino)acetophenones and Lipase-catalysed resolution of 2-(alkoxycarbonylamino)-1-arylethanols

Enzymatic reduction of α-(alkoxycarbonylamino)acetophenones with bakers yeast afforded optically active (R)-2-(alkoxycarbonylamino)-1-arylethanols. However, the reduction of α-(benzyloxycarbonylamino)-4-methoxyacetophenone (3c) with immobilized bakers yeast gave (S)-2-(benzyloxycarbonylamino)-1-(4-methoxyphenyl) ethanol. The lipase PS-catalysed transesterification of 2-(allyloxycarbonylamino)-1-arylethanols (5) using vinyl acetate as an acyl donor resulted in the formation of (S)-2-(allyloxycarbonyl-amino)-1-arylethyl acetates [(S)-9] and (R)-2-(allyloxycarbonylamino)-1-aryle-thanols [(R)-5].