Carborane terminal alkynes
Russ. Chem. Bull., Int. Ed., Vol. 67, No. 3, March, 2018
503
precipitate. Then, 3-trimethylsilylprop-2-ynal (0.88 g, 7 mmol)
was added to the mixture at –78 C, which was stirred for 30 min,
raising the temperature to ambient. The reaction mixture was
poured into 1 М HCl (25 mL), the organic phase was separated,
the aqueous phase was extracted with diethyl ether (10 mL). The
combined organic extracts were dried with Na2SO4. The solvent
was evaporated, the residue was recrystallized from methanol (5 mL).
The yield was 0.92 g (3.25 mmol, 51%), colorless crystals.
Found (%): C, 37.86; H, 7.81. C9H22B10OSi. Calculated (%):
С, 38.27; Н, 7.85. 1H NMR (CDCl3), : 5.13 (s, 1 H, CHO);
4.38 (d, 1 H, HCHO, J = 8.6 Hz); 4.26 (d, 1 H, HCHO,
J = 8.8 Hz); 3.13—1.47 (br.m, 10 H, BH); 0.24 (s, 9 H, CH3Si).
13C NMR (CDCl3), : 97.6 (HCC≡C); 95.6 (C≡CSi); 80.3
(Ccarb); 78.5 (Ccarb); 73.5(CHO); 73.0 (CH2O); 0.5 (CSi).
11B NMR (CDCl3), : –5.8 (d, 2 B, J = 166 Hz); –7.6 (d, 1 B,
J = 148 Hz); –8.2 (d, 2 B, J = 160 Hz); –10.2 (d, 1 B); –12.4
(d, 2 B, J = 159 Hz); –13.2 (d, 2 B, J = 175 Hz).
graphic parameters are available from the Cambridge Crystallo-
graphic Database (CCDC 1584790, www.ccdc.ac.uk).
This work was partially financially supported by the
Russian Foundation for Basic Research (Project No. 17-03-
00476). Elemental analysis, X-ray diffraction and NMR
spectroscopic studies were carried out in the Center of
Molecular Structure Studies of the A. N. Nesmeyanov
Institute of Organoelement Compounds of the Russian
Academy of Sciences.
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2-Ethynyl-3,4-(о-carborano)-2,5-dihydrofuran (4). The com-
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(CH2O). 11B NMR (CDCl3), : –5.8 (d, 2 B, J =151 Hz); –7.5
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pound 3 (0.2 g, 0.7 mmol) was dissolved in MeOH (10 mL),
after addition of two granules of NaOH, the mixture was refluxed
for 1 h with a reflux condenser. Then, MeOH was evaporated,
the residue was dissolved in 10% aqueous HCl (10 mL), followed
by the addition of an excess of the saturated aqueous solution of
trimethylamine hydrochloride. The product was collected by
filtration and dried in air. The yield was 0.174 g (0.67 mmol, 96%),
a white foam. Found (%): C, 41.17; H, 9.28; N, 5.43. C9H24B9NO.
Calculated (%): С, 41.64; Н, 9.32; N, 5.40. 1H NMR (acet-
one-d6), : 4.78 (d, 1 H, CHO, J = 2.2 Hz); 3.91 (d, 1 H, HCHO,
J = 7.8 Hz); 3.64 (d, 1 H, HCHO, J = 7.8 Hz); 3.22 (s, 9 H,
NMe3); 2.75 (d, 1 H, C≡CH, J = 2.2 Hz); 3.13—1.47 (br.m, 9 H,
BH); –2.67 (br.m, BH-bridging). 13C NMR (acetone-d6),: 81.0
(C≡CH); 76.8 (C≡CH); 72.8 (Ccarb); 72.5 (Ccarb); 71.8 (CHO);
71.6 (CH2O). 11B NMR (CDCl3), : –12.4 (d, 2 B, J = 135 Hz);
–16.1 (m, 1 B); –19.4 (m, 4 B); –31.3 (d, 1 B, J = 136 Hz); –36.1
(d, 1 B, J = 141 Hz).
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X-ray diffraction study of crystals of compound 3 was per-
formed on a Bruker APEX II Duo diffractometer (Mo-Kα ra-
diation, graphite monochromator, ω-scan technique). The
structures were solved by direct method and refined by the least
squares method in anisotropic full-matrix approximation with
respect to F2hkl. Hydrogen atoms were localized from difference
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approximation. The full X-ray diffraction data and crystallo-
Received November 23, 2017;
in revised form December 19, 2017;
accepted December 26, 2017