Naohiko Ikuma

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Organization: Osaka University
Department: Graduate School of Engineering
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Co-reporter:Naohiko Ikuma, Koji Nakagawa, Ken Kokubo and Takumi Oshima  
Organic & Biomolecular Chemistry 2016 vol. 14(Issue 29) pp:7103-7108
Publication Date(Web):29 Jun 2016
DOI:10.1039/C6OB00869K
Grignard reagents (RMgBr: R = Et, p-tolyl) selectively attacked the β-position of the bridgehead double bond of tosylazafulleroid through interaction of Mg with the SO group. The following [5,6] ring closure and C–N bond scission led to aryl/alkyl aminylfullerenes with 1,2-configuration. Tolyl-substituted aminylfullerene was further converted into 1,4-di(p-tolyl)fullerene on treatment in acidic toluene.
Co-reporter:Naohiko Ikuma, Koichi Fujioka, Yusuke Misawa, Ken Kokubo and Takumi Oshima  
Organic & Biomolecular Chemistry 2015 vol. 13(Issue 17) pp:5038-5043
Publication Date(Web):16 Mar 2015
DOI:10.1039/C5OB00272A
Oxidation of azafulleroids with peracids regenerated C60 depending on the N-substituents. Alkyl-substituted azafulleroids preferred the oxidation of nitrogen to afford N-oxides as possible intermediates for C60 in moderate yields. Phenyl- and tosyl-substituted azafulleroids rather allowed the oxidation at the carbon cage. Theoretical calculations predicted the order of reactivity of azafulleroids as well as the relative N/C nucleophilicity.
Co-reporter:Naohiko Ikuma, Saori Inaba, Ken Kokubo and Takumi Oshima  
Chemical Communications 2014 vol. 50(Issue 5) pp:581-583
Publication Date(Web):22 Oct 2013
DOI:10.1039/C3CC45783D
Triazoliumfullerene was first prepared by the [3+2] cycloaddition of in situ generated 1,3-diaza-2-azoniaallene with fullerene and was characterized by the dispersed positive charge over the fullerene sphere associated with periconjugation. This new type of amphiphilic fullerene tended to form vesicles and crystalline aggregates after the casting of THF or MeOH solutions.
Co-reporter:Dr. Naohiko Ikuma;Yuta Doi;Koichi Fujioka;Tsubasa Mikie;Dr. Ken Kokubo ;Dr. Takumi Oshima
Chemistry – An Asian Journal 2014 Volume 9( Issue 11) pp:3084-3088
Publication Date(Web):
DOI:10.1002/asia.201402728

Abstract

Azafulleroid, amino-bridged [5,6]-open fullerene, has the ambident N/C basicity of the incorporated enamine moiety. Acid-catalyzed arylation of N-substituted azafulleroids proceeded via two types of initial N/C protonation to perform monoarylation or 1,4-bisarylation for the N-alkyl substituents and shuttlecock-type pentakisarylation for the N-phenyl substituent. The dramatic product change was explained by considering the possible mechanism as well as the DFT computational results.

Co-reporter:Naohiko Ikuma, Tsubasa Mikie, Yuta Doi, Koji Nakagawa, Ken Kokubo, and Takumi Oshima
Organic Letters 2012 Volume 14(Issue 23) pp:6040-6043
Publication Date(Web):November 27, 2012
DOI:10.1021/ol302928d
Variously substituted [6,6]closed aziridinofullerenes were exclusively obtained from acid-catalyzed denitrogenation of triazolinofullerenes without formation of relevant [5,6]open azafulleroids, which are the major products on noncatalyzed denitrogenation. The mechanistic consideration by DFT calculations suggested a reaction sequence involving initial pre-equilibrium protonation of the triazoline N1 atom, generation of aminofullerenyl cation by nitrogen-extrusion, and final aziridination.
Co-reporter:Naohiko Ikuma, Satoko Sumioka, Haruyasu Asahara, Takumi Oshima
Tetrahedron Letters 2012 Volume 53(Issue 28) pp:3581-3584
Publication Date(Web):11 July 2012
DOI:10.1016/j.tetlet.2012.05.007
The mCPBA oxidation of methano-bridged [5,6] open fulleroid 1 anomalously resulted in the selective electrophilic addition at the bridgehead anti-Bredt double bond rather than the usual epoxidation. The mechanistic preference for the unprecedented stepwise addition of mCPBA vs the concerted epoxidation was explained in terms of the notable π-orbital misalignment (>30°) based on the B3LYP/6-31G(d) level calculation.
Co-reporter:Naohiko Ikuma, Saori Inaba, Ken Kokubo and Takumi Oshima
Chemical Communications 2014 - vol. 50(Issue 5) pp:NaN583-583
Publication Date(Web):2013/10/22
DOI:10.1039/C3CC45783D
Triazoliumfullerene was first prepared by the [3+2] cycloaddition of in situ generated 1,3-diaza-2-azoniaallene with fullerene and was characterized by the dispersed positive charge over the fullerene sphere associated with periconjugation. This new type of amphiphilic fullerene tended to form vesicles and crystalline aggregates after the casting of THF or MeOH solutions.
Co-reporter:Naohiko Ikuma, Koichi Fujioka, Yusuke Misawa, Ken Kokubo and Takumi Oshima
Organic & Biomolecular Chemistry 2015 - vol. 13(Issue 17) pp:NaN5043-5043
Publication Date(Web):2015/03/16
DOI:10.1039/C5OB00272A
Oxidation of azafulleroids with peracids regenerated C60 depending on the N-substituents. Alkyl-substituted azafulleroids preferred the oxidation of nitrogen to afford N-oxides as possible intermediates for C60 in moderate yields. Phenyl- and tosyl-substituted azafulleroids rather allowed the oxidation at the carbon cage. Theoretical calculations predicted the order of reactivity of azafulleroids as well as the relative N/C nucleophilicity.
Co-reporter:Naohiko Ikuma, Koji Nakagawa, Ken Kokubo and Takumi Oshima
Organic & Biomolecular Chemistry 2016 - vol. 14(Issue 29) pp:NaN7108-7108
Publication Date(Web):2016/06/29
DOI:10.1039/C6OB00869K
Grignard reagents (RMgBr: R = Et, p-tolyl) selectively attacked the β-position of the bridgehead double bond of tosylazafulleroid through interaction of Mg with the SO group. The following [5,6] ring closure and C–N bond scission led to aryl/alkyl aminylfullerenes with 1,2-configuration. Tolyl-substituted aminylfullerene was further converted into 1,4-di(p-tolyl)fullerene on treatment in acidic toluene.
Clevios P-VP-AI 4083
1'H-[5,6]Fullereno-C60-Ih-[1,9-b]azirine, 1'-[(4-methylphenyl)sulfonyl]-
Fullerene epoxide
Benzene, 5-(azidomethyl)-1,2,3-trimethoxy-
1-((3-chlorophenyl)sulfonamido)cyclohexane-1-carboxylic acid
2-ethenylbenzenesulfonic acid