Pentagon-Fused Sumanenes on the Aromatic Peripheries en Route to the Bottom-Up Synthesis of Fullerenes
Hironobu Nakazawa
a
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
,
Yuta Uetake
a
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
b
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
,
Yumi Yakiyama
a
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
b
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
a
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
b
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
› Author AffiliationsThis work was supported by JSPS KAKENHI, grant nos. JP26102002, JP21H05233, JP19H00912, JP20H00400 (H.S.), and JP20K15279 (Y.U.). and Grant-in-Aid for JSPS Research Fellow JP21J10937 (H.N.).
Bowl-shaped π-conjugated sumanenyltriamines were successfully synthesized in a one-step reaction from bromomethylsumanene. This molecule represents an example of hemiazafullerene (C54N6 fragment) with six isolated pentagons. Its single-crystal X-ray structural analysis showed the formation of one-dimensional columnar structures incorporating chloroform. The hemifullerene (C30 fragment) was also synthesized when the nucleophile was changed to dimethylmalonate.
19General Procedures for the Synthesis of 2
To a reaction vial equipped with a magnetic stir bar were added 1 (40.0 mg, 49.1 μmol, 100 mol%) and solvent (4.0 mL). To this was added amine 3 (900 mol%) and the mixture was stirred at 80 °C for 10 min. After cooling to room temperature, H2O was added and the mixture was extracted with EtOAc. The combined organic extract was washed with brine and dried over Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography to give sumanenyltriamines 2.
21Hexamethyl 3,4,5,7,8,9,11,12-Octahydrohexacyclopenta-[b, def,h,jkl,n,pqr]triphenylene-2,2,6,6,10,10(1H)-hexacarboxylate (4a): To a test tube equipped with a magnetic stir bar were added 1 (10.0 mg, 12.3 μmol, 100 mol%), K2CO3 (20.3 mg, 147 μmol, 1200 mol%), and THF (1.5 mL). To this was added dimethyl malonate (4.9 μL, 36.8 μmol, 350 mol%) and the mixture was stirred at 80 °C for 48 h. After cooling to room temperature, H2O was added and the reaction mixture was extracted with EtOAc. The combined organic extract was washed with brine and dried over Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography (EtOAc/CHCl3/n-hexane = 10:5:7) followed by GPC (CHCl3) to give 4a (3.1 mg, 4.2 μmol, 34%) as a colorless solid. Mp 246 °C (dec); TLC: Rf = 0.61 (EtOAc/CHCl3/n-hexane = 10:5:7). IR (KBr): 3461, 3001, 2953, 2845, 1736, 1434, 1282, 1242, 1201, 1161, 1070 cm−1. 1H NMR (400 MHz, CDCl3): δ = 4.48 (d, J = 19.4 Hz, 3 H), 3.82 (s, 9 H), 3.73 (d, J = 16.7 Hz, 6 H), 3.62 (s, 9 H), 3.38 (d, J = 16.7 Hz, 6 H), 3.29 (d, J = 19.4 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 172.41 (3C), 172.04 (3C), 147.43 (6C), 143.57 (6C), 135.82 (6C), 60.36 (3C), 53.31 (3C), 53.13 (3C), 39.20 (3C), 39.04 (6C). HRMS (ESI+): m/z calcd for C42H36O12 [M + Na]+: 755.2099; found: 755.2092.
