H. Frauenrath et al.
A
perature and stirred for another 2 h. Then, the reaction was cooled to
08C, and trimethylsilylchloride (43.45 g, 400 mmol) was added slowly, fol-
lowed by stirring the reaction mixture at room temperature for 20 min.
The solvent was removed in vacuo and the black-brown residue was re-
dissolved in CH2Cl2. After aqueous workup, the crude product 4 (36.38 g,
94%) was obtained as a dark brown solid. Further purification was car-
ried out by sublimation, yielding 4 (32.9 g, 85%) as colorless crystals. Rf
not detectable on the TLC plate; m.p. 1118C. 1H NMR (300 MHz,
CDCl3): d=0.18 ppm (s, 18H; SiMe3); 13C NMR (75 MHz, CDCl3): d=
CH2Cl2. Triethylamine (0.15 mL, 1.05 mmol, 3 equiv) was added to the
solution and the mixture was stirred for 3 h in the dark. After aqueous
workup, the organic phase was concentrated and purified by column
chromatography (CH2Cl2/hexanes 1:4, gradient to pure CH2Cl2). The
pure product 2a (0.124 g, 82%) was obtained as colorless crystals, which
turned to a light purple when the solutions were concentrated. Product
2a was stored as a solution in CH2Cl2 at 48C. Crystals appropriate for X-
ray analysis were prepared by slow addition of hexanes to a 20% w/w so-
lution of the product in CH2Cl2 until opalescence occurred, and subse-
quent slow evaporation of the solvent in dark. Rf =0.71 (CH2Cl2); m.p.
107.58C (DSC); 1H NMR (300 MHz, CDCl3): d=8.05 (m, 2H; PhHo),
7.59 (m, 1H; PhHp), 7.45 (m, 2H; PhHm), 5.04 (s, 2H; CH2), 5.00 ppm (s,
2H; CH2); 13C NMR (75 MHz, CDCl3):[44] d=165.5 (C=O), 158.2, 145.7,
143.7, 137.7, 106.9 (C6F5), 133.5, 129.8, 129.0, 128.5 (Ph), 73.2, 72.3, 71.1,
ꢀ
88.0, 85.9 (C C), À0.5 ppm (SiMe3); elemental analysis calcd (%) for
C10H18Si2: C 61.78, H 9.33, Si 28.89; found: C 61.78, H 9.54; MS: m/z
calcd for C10H18Si2 [M]+: 194.0947; found: 194.0900.
5-(Trimethylsilyl)-2,4-pentadiyn-1-ol (5):[27] In a thoroughly dried Schlenk
flask under an N2 atmosphere, 4 (7.78 g, 40 mmol, 1 equiv) was dissolved
in dry Et2O (400 mL), and MeLi·LiBr complex in hexanes (1.5m,
34.7 mL, 52 mmol, 1.3 equiv) was added to this solution. The reaction
mixture was kept stirring for 1 d. During this time it turned to a greenish
color and became turbid. Paraformaldehyde (3.6 g, 120 mmol, 3 equiv)
was added in one portion, and the reaction was stirred for another 2 d.
The reaction was subjected to an aqueous workup, and the crude product
was purified by column chromatography (EtOAc/hexanes 7:1). The pure
70.9, 63.6, 62.5 (C C), 54.1, 52.6 ppm (CH2); 19F NMR (188 MHz,
CDCl3): d=À136.9 (m, 2F), À146.9 (m, 1F), À159.8 ppm (m, 2F); ele-
mental analysis calcd (%) for C22H9O4F5: C 61.12, H 2.10, O 14.80, F
21.97; found: C 61.27, H 2.22, F 21.91; HRMS (EI): m/z calcd for
C22H9O4F5 [M]+: 432.0421; found: 432.0413.
8-[4-(Dodecyloxy)benzoyloxy]octa-2,4,6-triynyl 2,3,4,5,6-pentafluoroben-
zoate (2b): The monosubstituted intermediate 9b (0.21 g, 0.5 mmol,
1 equiv) and pentafluorobenzoyl chloride (0.12 g, 0.5 mmol, 1 equiv)
were dissolved in dry CH2Cl2. Triethylamine (0.28 mL, 2 mmol, 4 equiv)
was added to the solution and the mixture was stirred for 3 h. After
aqueous workup, the organic solution was concentrated and purified by
column chromatography (CH2Cl2/hexanes 2:3). The pure product 2b
(0.26 g, 85%) was obtained as supposedly colorless crystals, which un-
avoidably turned slightly purple when the solutions were concentrated.
Therefore, 2b was stored as a solution in CH2Cl2 at 48C. Rf =0.50
(CH2Cl2/hexanes 1:1); m.p. 88.68C (DSC); 1H NMR (300 MHz, CDCl3):
d=7.98 (m, 2H; PhHm-COO), 6.90 (m, 2H; PhHo-COO), 5.04 (s, 2H;
product
(EtOAc/hexanes 1:2); 1H NMR (300 MHz, CDCl3): d=4.29 (d, J=3 Hz,
2H; CH2), 3.00 (s, 1H; OH), 0.16 ppm (s, 9H; Si
(CH3)3); 13C NMR
5 (4.26 g, 70%) was obtained as a yellow liquid. Rf =0.44
AHCTUNGTRENNUNG
ꢀ
(75 MHz, CDCl3): d=87.5, 87.1, 75.7, 70.4 (C C), 51.0 (CH2), À0.6 ppm
(SiMe3); elemental analysis calcd (%) for C8H12OSi: C 63.10, H 7.94, O
10.51, Si 18.44; found: C 62.89, H 7.80; HRMS: m/z calcd for C8H12OSi
[M]+: 152.0657; found: 152.0655.
Penta-2,4-diyn-1-ol (6):[28] 5-(Trimethylsilyl)-2,4-pentadiyn-1-ol (5; 1.52 g,
10 mmol, 1 equiv) was added to a solution of K2CO3 (2.01 g, 15 mmol,
1.5 equiv) in MeOH (150 mL). The mixture was stirred in the dark for
2 h during which its color changed from slight yellow to brown. The reac-
tion was worked up by concentrating the reaction mixture to a brown
syrup, diluting it with Et2O, and washing it with saturated aqueous
NH4Cl solution and saturated aqueous NaCl solution. The organic phase
was dried and concentrated, affording the crude 6 (0.72 g, 90%) as a
brown liquid. This crude product was used in the next steps without fur-
ther purification. For storage purposes, it was kept as a solution in Et2O
at 48C. Rf =0.12 (EtOAc/hexanes 1:5); 1H NMR (300 MHz, CDCl3): d=
OCH2C C), 4.96 (s, 2H; OCH2C C), 4.00 (t, J=7.5 Hz, 2H; OCH2CH2),
1.80 (m, 2H; OCH2CH2), 1.46–1.26 (m, 18H; (CH2)9Me), 0.88 ppm (t,
J=6 Hz, 3H; CH3). 13C NMR (75 MHz, CDCl3):[44] d=165.2 (C=O),
163.5, 131.9, 121.0, 114.2 (Ph), 73.5, 72.3, 70.9, 70.8 (C C), 68.3
(OCH2CH2), 63.7, 62.4 (C C), 54.1, 52.3 (OCH2C C), 31.9, 29.6–29.1
(7C), 25.9, 22.7 (CH2), 14.1 ppm (CH3); 19F NMR (188 MHz, CDCl3): d=
À137.0 (m, 2F), À147.0 (m, 1F), À159.9 ppm (m, 2F); elemental analysis
calcd (%) for C34H33O5F5: C 66.23, H 5.39, O 12.97, F 15.41 found: C
66.14, H 5.57, F 15.36; HRMS (EI): m/z calcd for C34H33O5F5 [M]+:
616.2248; found: 616.2286.
ꢀ
4.27 (s, 2H; CH2), 3.70 (s, 1H; OH), 2.22 ppm (m, 1H; C CH);
13
ꢀ
C NMR (75 MHz, CDCl3): d=74.3, 69.5, 68.5, 67.2 (C C), 50.6 ppm
(CH2).
3-Iodoprop-2-yn-1-ol (7):[29] A solution of propargyl alcohol (5.8 mL,
100 mmol, 1 equiv) in methanol (100 mL) was added slowly to a solution
of potassium hydroxide (14 g, 250 mmol, 2.5 equiv) in H2O (20 mL) at
08C. The mixture was stirred for 10 min. Then, iodine (27 g, 110 mmol,
1.1 equiv) was added in one portion. The reaction mixture was allowed
to warm up to room temperature and stirred for 3 h before it was extract-
ed with Et2O. The combined organic phases were washed with Na2S2O3
and brine. Upon concentration of the solution in vacuo, 7 (14.58 g, 80%)
was obtained in the form of yellow crystals. Rf =0.70 (CH2Cl2/MeOH
2,4,6-Octatriynylene bis(pentafluorobenzoate) (3): Octa-2,4,6-triyne-1,8-
diol (8; 0.094 g, 0.7 mmol, 1 equiv) and pentafluorobenzoyl chloride
(0.323 g, 1.4 mmol, 2 equiv) were dissolved in dry CH2Cl2. Triethylamine
(0.39 mL, 2.8 mmol, 4 equiv) was added to the solution and the mixture
was stirred for 3 h in the dark. After aqueous workup, the organic solu-
tion was concentrated and purified by column chromatography (CH2Cl2).
The pure product 8 (0.35 g, 95%) was obtained as colorless crystals and
stored as a solution in CH2Cl2 at 48C. Rf =0.67 (CH2Cl2); m.p. 71.38C
(DSC); 1H NMR (300 MHz, CDCl3): d=5.07 ppm (s, 4H; CH2);
13C NMR (75 MHz, CDCl3):[44] d=158.1 (C=O), 145.8, 143.8, 137.8, 106.9
10:1); 1H NMR (300 MHz, CDCl3): d=4.39 (s, 2H; CH2), 3.18 ppm (s,
(C6F5), 72.0, 71.4, 63.1 (C C), 54.0 ppm (CH2); 19F NMR (188 MHz,
13
ꢀ
ꢀ
1H; OH); C NMR (75 MHz, CDCl3): d=92.4 (C CI), 52.1 (CH2),
CDCl3): d=À137.2 (m, 4F), À147.1 (m, 2F), À160.1 ppm (m, 4F); ele-
mental analysis calcd (%) for C22H4F10O4: C 50.60, H 0.77, F 36.38, O
12.25; found: C 50.56, H 0.96, F 36.19; HRMS (EI): m/z calcd for
C22H4F10O4 [M]+: 521.9950; found: 521.9944.
ꢀ
2.8 ppm (C CI); elemental analysis calcd (%) for C3H3IO: C 19.80, H
1.66, O 8.79, I 69.74; found: C 19.86, H 1.68, O 8.93, I 69.70; HRMS
(EI): m/z calcd for C3H3IO [M]+: 181.9229; found: 181.9229.
Octa-2,4,6-triyne-1,8-diol (8):[6,30] CuCl (0.024 g, 0.24 mmol, 0.04 equiv)
was dissolved in a mixture of MeOH (2 mL) and nBuNH2 (3 mL). Then,
6 (0.58 g, 7.2 mmol, 1.2 equiv) dissolved in Et2O (1 mL) was added at
08C, followed by the dropwise addition of 7 (1.09 g, 6 mmol, 1 equiv) in
Et2O (2 mL). Whenever the reaction mixture turned green, a few crystals
of NH2OH·HCl were added. After stirring for 1 h at 08C and for another
1 h at room temperature, the reaction mixture was diluted with Et2O and
filtered through a pad of silica gel. After aqueous workup, the crude
product was purified by column chromatography (EtOAc/hexanes 1:3),
affording pure 8 (0.34 g, 42%) as colorless crystals. The product was un-
stable in daylight in the solid state and stored as a solution in a Et2O at
48C. Rf =0.30 (EtOAc/hexanes 1:2); 1H NMR (300 MHz, CD3OD): d=
Cocrystal 1a·3: The cocrystals 1a·3 for X-ray analysis were obtained as
light purple needles by addition of hexanes to a 20% w/w solution of a
1:1 mixture of 1a and 3 in CH2Cl2 until opalescence occurred, and subse-
quent slow evaporation of the solvent. M.p. 93.88C (DSC); elemental
analysis calcd (%) for C44H18F10O8: C 61.12, H 2.10, O 14.80, F 21.97;
found: C 61.07, H 2.19, F 22.19.
Bis(trimethylsilyl)butadiyne (4):[25] A dry 2 L Schlenk flask filled with dry
THF (500 mL) was cooled to À788C, and n-butyllithium (320 mL, 2.5m
solution in hexanes, 800 mmol) was added. Then, hexachlorobutadiene
(52.15 g, 200 mmol) was added dropwise under vigorous stirring, forming
a black precipitate. The reaction was allowed to warm up to room tem-
9114
ꢄ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 9105 – 9116