|Masahiko Suenaga||Last modified date：2021.09.01|
Lecturer / Multidisciplinary Chemistry / Department of Chemistry / Faculty of Sciences
|1.||Chotika Phupong, Masahiko Suenaga, Phuangthip Bhoopong, Warangkana Chunglok, Gunlanan Jaritngam, Milandip Karak, Keiichi Yoshida, Worrapong Phupong, Kohei Torikai, Precise 1H- and 13C-NMR reassignment of dehydrocrebanine by 10-mg INADEQUATE and in silico analysis: With an alert for its toxicity, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131310, 76, 27, Article 131310, 2020.07.|
|2.||Milandip Karak, Yohei Joh, Masahiko Suenaga, Tohru Oishi, Kohei Torikai, 1,2-trans Glycosylation via Neighboring Group Participation of 2- O-Alkoxymethyl Groups
Application to One-Pot Oligosaccharide Synthesis, Organic Letters, 10.1021/acs.orglett.9b00220, 21, 4, 1221-1225, 2019.02, The use of 2-O-alkoxymethyl groups as effective stereodirecting substituents for the construction of 1,2-trans glycosidic linkages is reported. The observed stereoselectivity arises from the intramolecular formation of a five-membered cyclic architecture between the 2-O-alkoxymethyl substituent and the oxocarbenium ion, which provides the expected facial selectivity. Furthermore, the observed stereocontrol and the extremely high reactivity of 2-O-alkoxymethyl-protected donors allowed development of a one-pot sequential glycosylation strategy that should become a powerful tool for the assembly of oligosaccharides..
|3.||Masahiko Suenaga, Kazuhide Nakata, José Luis M. Abboud, Masaaki Mishima, A natural bond orbital analysis of aryl-substituted polyfluorinated carbanions
negative hyperconjugation, Journal of Physical Organic Chemistry, 10.1002/poc.3721, 31, 1, 2018.01, Aryl-substituted polyfluorinated carbanions, ArCHRf − where Rf = CF3 (1), C2F5 (2), i-C3F7 (3), and t-C4F9 (4), were analyzed by means of the natural bond orbital (NBO) theory at the B3LYP/6-311+G(d,p) computational level. A lone pair NBO at the formal anionic center carbon (Cα) was not found in the Lewis structure. Instead, significant donor/acceptor NBO interactions between π(Cα-C1) and σ*(Cβ-F) or σ*(Cβ-Cγ) were observed for 1, 2, 3a (strong electron-withdrawing substituent, from p-CF3 to p-NO2), and 4. Their second-order donor/acceptor perturbation interaction energy, E(2), values decreased with the increase of the stability of carbanions. A larger E(2) value corresponds to longer Cβ-F and Cβ-Cγ bonds and a shorter Cα-Cβ bond, indicating that the E(2) values can be associated with the negative hyperconjugation of the Cβ-F and Cβ-Cγ bonds. In accordance with this, the E(2) values for π(Cα-C1) → σ*(Cβ-F) were linearly correlated with the ΔGo β-F values (an empirical measure of β-fluorine negative hyperconjugation obtained from an increased acidity). In 3b (weak electron-withdrawing substituents, from H to m-NO2) very large E(2) values for LP(Fβ) → π*(Cα-Cβ) were obtained. This was attributed to the Cβ-F bond cleavage and the Cα-Cβ double bond formation in the Lewis structure that is caused by the extremely strong negative hyperconjugation of the Cβ-F bond..
|4.||Masahiko Suenaga, Kazuhide Nakata, José Luis M. Abboud, Masaaki Mishima, Negative hyperconjugation in acidity of polyfluorinated alkanes. A natural bond orbital analysis, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20160353, 90, 3, 289-297, 2017.01, Natural bond orbital (NBO) analysis has been applied to various polyfluorinated carbanions. The E(2)[LP(Cα)→σ∗(Cβ-F) or σ∗(Cβ-Cγ)] values that are interaction energies between a lone pair NBO at the anionic center carbon and the σ∗(Cβ-F) or σ∗(Cβ-Cγ) NBO increased with the corresponding Cβ-F or Cβ-Cγ bond distances, respectively, being consistent with the molecular orbital theory on negative hyperconjugation. The total E(2) values for the interactions of a lone pair orbital with all σ∗(Cβ-F) and σ∗(Cβ-Cγ) orbitals were linearly correlated with gas-phase acidities of the corresponding alkanes, giving two lines for the carbanions having no β-fluorine atom and for the primary and secondary carbanions having β-fluorine atoms (slopes of 0.57 and 1.56, respectively). The major E(2)[LP(Cα)→σ∗(Cβ-F)] values in the respective anions were found to be linearly correlated with the ΔG°β-F values as an empirical measure of β-fluorine negative hyperconjugation obtained from an increased acidity of the molecule owing to the presence of β-fluorine. However, the magnitude of ΔG°β-F was much smaller than the E(2)[LP(Cα)→σ∗(Cβ-F)] value, indicating that the absolute values of the β-fluorine negative hyperconjugation are smaller than the E(2) interaction energies..|
|5.||Masaaki Mishima, José-Luis M. Abboud, Mizue Fujio, Masahiko Suenaga, Heinz F. Koch, Judith G. Koch, Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds.
Experimental and Computational Studies, 10.1002/poc.3576, 29, 523-531, 2016.05, The gas-phase acidities (GA) of 2-aryl-2-chloro-1,1,1-trifluoroethanes (1a), 2-aryl-2-fluoro-1,1,1-trifluoroethanes (2a), and related compounds, XC6H4CH(Z)R where Z = Cl (1) or F (2) and R = C2F5 (b), t-C4F9 (c), C(CF3)2C2F5 (d), C(CF3)2Me (e), Me (f),H (g), were investigated experimentally and computationally. On the basis of an excellent linear correlation (R2>0.99) of acidities of 1c-f and 2c-f where there is no fluorine atom at β-position to the deprotonation site with the corrected number of fluorine atoms contained in the fluorinated alkyl group, the extent of β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔGoβ-F) was evaluated. The GAel values given by subtraction ΔGoβ-F from the apparent GA value were considered to represent the electronic effect of the substituent X. The substituent effects on the GAel values and GA values for 1c-f and 2c-f were successfully analyzed in terms of the Yukawa–Tsuno equation. The variation of resonance demand parameter r with the R group observed for various XC6H4CH(Z)R was linearly related to the GA (GAel) value of the respective phenylsubstituted
fluorinated alkanes. On the other hand, the corresponding correlation for the ρ values provided three lines
for ArCH(Cl)R, ArCH(F)R and ArCH2R, respectively. These results supported our previous conclusion that the r and ρ values are governed by the thermodynamic stability of the parent ion (ring substituent = H). Other factors arising from an atom bonded to the acidic center also influence the ρ value..
|6.||Mariappan Mariappan, Masahiko Suenaga, Abhik Mukhopadhyay, Pallepogu Raghavaih, and Bhaskar G. Maiya, Synthesis, structure, DNA binding and photocleavage activity of a ruthenium(II) complex with 11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine ligand, Inorganica Chimica Acta, 10.1016, 376, 340, 2011.08.|
|7.||Kikuko Hayamizu, Seiji Tsuzuki, Shiro Seki, Kenta Fujii, Masahiko Suenaga, and Yasuhiro Umebayashi, Studies on the translational and rotational motions of ionic liquids composed of N-methyl-N-propyl-pyrrolidinium (P13) cation and bis(trifluoromethanesulfonyl)amide and bis(fluorosulfonyl)amide anions and their binary systems including lithium salts, The Journal of Chemical Physics, 133, 194505, 2010.11.|
|8.||M. Shibahara, M. Watanabe, M. Suenaga, K. Ideta, T. Matsumoto, and T. Shinmyozu, A Conformational Study of [3.3](3,5)Pyridinophane, Tetrahedron Letters, 50, 1340, 2009.03.|
|11.||Facio: New Computational Chemistry Environment for PC GAMESS
M. Suenaga, Journal of Computer Chemistry, Japan, Vol. 4, No. 1 pp. 25-32 (2005).
|12.||The Model Of A Supermolecule With Dodecahedral Symmetry
M. Suenaga, Journal of Computer Chemistry, Japan, Vol. 3, No. 1 pp.27-34 (2004).
|13.||Development Of A Server/Client Type Reagent Management System (Servo) Using PostgreSQL As A Database
M. Suenaga, Journal of Computer Chemistry, Japan, Vol. 2, No. 1 pp.41-48 (2003).
|14.||Y. Miyahara, Y. Tanaka, K. Amimoto, T. Akazawa, T. Sakuragi, H. Kobayashi, K. Kubota, M. Suenaga, H. Koyama, and T. Inazu, The Proton Cryptate of Hexaethylenetetramine, Angew. Chem. Int. Ed., 10.1002/(SICI)1521-3773(19990401)38:7<956::AID-ANIE956>3.3.CO;2-B, 38, 7, 956-959, 38, 956-959 (1999), 1999.04.|
|15.||A. A. Ibrahim, M. Matsumoto, Y. Miyahara, K. Izumi, M. Suenaga, N. Shimizu, and T. Inazu, Synthesis and Properties of a New Series of Troegaropnanes, J. Heterocyclic Chem., 35, 1, 209-215, 35, 209-215 (1998), 1998.01.|
|16.||M. Suenaga, Y. Miyahara, N. Shimizu, and T. Inazu, Synthesis of the Trinaphthophenalenium Cation, Angew. Chem. Int. Ed., 10.1002/(SICI)1521-3773(19980202)37:1/2<90::AID-ANIE90>3.3.CO;2-7, 37, 1-2, 90-91, 37, 90-91 (1998), 1998.01.|
|17.||M. Suenaga, Y. Miyahara, and T. Inazu, A Novel Approach to Extended Phenalenones, J. Org. Chem., 10.1021/jo00073a054, 58, 21, 5846-5848, 58, 5846-5848 (1993), 1993.07.|
|18.||I. U. Khan, H. Takemura, M. Suenaga, T. Shinmozu, and T. Inazu, Azacalixarenes: New Macrocycles with Dimethyleneaza-Bridged Calixarene Systems, J. Org. Chem., 10.1021/jo00063a042, 58, 11, 3158-3161, 58, 3158-3168 (1993), 1993.07.|
|19.||K. Sako, T. Shinmyozu, H. Takemura, M. Suenaga, and T. Inazu, A Conformational Study of [3.3]Metacyclophanes Through Variable
Temperature 1H NMR and Optical Rotation, J. Org. Chem., 10.1021/jo00050a031, 57, 24, 6536-6541, 57, 6536-6541 (1992), 1992.09.
|20.||T. Meno, K. Sako, M. Suenaga, M. Mouri, T. Shinmyozu, and T. Inazu, Conformational Analysis of [3.3.3](1,3,5)Cyclophane Systems, Can. J. Chem., 10.1139/v90-067, 68, 3, 440-445, 68, 440-445. (1990), 1990.02.|
|21.||H. Takemura, M. Suenaga, K. Sakai, H. Kawachi, T. Shinmyozu, Y. Miyahara, and T. Inazu, Synthesis of (Aza)n[3n]Cyclophanes As Host Molecules, Journal of Inclusion Phenomena, 2, 207-214 (1984), 1984.03.|
|22.||K. Kurosawa, M. Suenaga, T. Inazu, and T. Yoshino, A Facile Synthesis of [3n]Cyclophanes, in which Aromatic
Rings Are Connected With -CH2-CO-CH2- Bridges, Tetrahedron Letters, 10.1016/S0040-4039(00)85832-3, 23, 50, 5335-5338, Tetrahedron Lett., 23, 5335-5338 (1982), 1982.06.