160
Bull. Chem. Soc. Jpn. Vol. 84, No. 2 (2011)
Cyanochalcogenation of Alkynes
(PPh3)4]- and [Co2(CO)8]-catalyzed cyanothiolation of terminal
alkynes with thiocyanates has been disclosed. Oxidative
addition of thiocyanates to the palladium(0) complex was
confirmed by X-ray analysis. In addition, the [Co2(CO)8]-
catalyzed cyanoselenation of terminal alkynes with selenocya-
nates in the pressure of carbon monoxide has been also
developed.
Calcd for C15H19NS: C, 73.42; H, 7.80; N, 5.71%. Found: C,
73.16; H, 7.94; N, 5.25%.
(E)-3-(Phenylthio)-2-nonenenitrile ((E)-3a) (Table 2):
Pale red-brown oil; 1H NMR (300 MHz, CDCl3): ¤ 0.91 (t,
J = 6.6 Hz, 3H), 1.30-1.46 (m, 6H), 1.71 (quint, J = 7.4 Hz,
2H), 2.63 (t, J = 7.8 Hz, 2H), 4.46 (s, 1H), 7.47-7.52 (m, 5H);
13C NMR (68 MHz, CDCl3): ¤ 14.0, 22.5, 28.7, 29.2, 31.4,
35.5, 89.4, 116.9, 128.6, 130.1, 130.4, 135.6, 169.4; IR (NaCl):
3057, 2956, 2929, 2858, 2210 (CN), 1579, 1476, 1466, 1441,
1068, 1024, 790, 751, 705, 691 cm¹1; MS (EI): m/z = 245
(M+, 26). Anal. Calcd for C15H19NS: C, 73.42; H, 7.80; N,
5.71%. Found: C, 73.19; H, 7.80; N, 5.43%.
General Procedure for the [Pd(PPh3)4]-Catalyzed Cyano-
thiolation of Alkynes with Thiocyanates. Method A (the
cyanothiolation in solvents): In a 50 mL stainless steel
autoclave with a magnetic stirring bar under an argon
atmosphere were placed [Pd(PPh3)4] (0.1 mmol), benzene
(1 mL), alkyne (1.0 mmol), and thiocyanate (1.0 mmol). The
vessel was purged three times with argon and then charged at
0.1 MPa. The reaction was conducted with magnetic stirring for
66 h upon heating at 120 °C. After carbon monoxide was
purged, the precipitates were filtered through Celite and
concentrated in vacuo. Purification of the product was carried
out by MPLC eluted with hexane/Et2O.
Method B (the cyanothiolation in the absence of solvents):
In a flame-dried two-necked flask (20 mL) with a reflux
condenser and a magnetic stirring bar under a nitrogen
atmosphere were placed [Pd(PPh3)4] (0.1 mmol), alkyne (1.0
mmol), and thiocyanate (1.0 mmol). The reaction was con-
ducted with magnetic stirring for 20-66 h upon heating at
120 °C. After the reaction was complete, the precipitates were
filtered through Celite and concentrated in vacuo. Purification
of the product was carried out by recycling preparative HPLC
and TLC (PTLC).
(Z)-6-Methyl-3-(phenylthio)-2-heptenenitrile (3b) (Table 5,
Entry 1): Brown oil; 1H NMR (300 MHz, CDCl3): ¤ 0.72 (d,
J = 6.2 Hz, 6H), 1.25-1.40 (m, 3H), 2.15 (t, J = 7.6 Hz, 2H),
5.30 (s, 1H), 7.38-7.52 (m, 5H); 13C NMR (68 MHz, CDCl3): ¤
22.0, 27.3, 34.2, 37.5, 93.3, 116.1, 129.3, 129.3, 129.6, 134.9,
165.9; IR (NaCl): 3059, 2957, 2930, 2869, 2211 (CN), 1573,
1441, 1386, 1368, 1309, 1082, 1069, 1024, 749, 706,
692 cm¹1; MS (EI): m/z = 231 (M+, 8.5). Anal. Calcd for
C14H17NS: C, 72.68; H, 7.41; N, 6.05%. Found: C, 72.33; H,
7.39; N, 5.99%.
Experimental
General. 1H NMR spectra were recorded on JEOL JNM-
GSX 270 (270 MHz), JEOL JNM-AL 400 (400 MHz), or
Varian GEMINI 2000 (300 MHz) spectrometers using CDCl3
as the solvent with Me4Si as the internal standard. 13C NMR
spectra were taken on JEOL JNM-GSX-270 (68 MHz), JEOL
JNM-GSX-400 (100 MHz), or Varian GEMINI 2000 (75 MHz)
spectrometers using CDCl3 as the solvent. 31P NMR spectra
were taken on JEOL-JNM-ECP 500 (202 MHz) spectrometers
1
using CDCl3 as the solvent. Chemical shifts in H NMR were
measured relative to CDCl3 and converted to ¤ (Me4Si) value
by using ¤ (CDCl3) = 7.26. Chemical shifts in 13C NMR were
measured relative to CDCl3 and converted to ¤ (Me4Si) value
by using ¤ (CDCl3) = 77.0. IR spectra were determined on a
Perkin-Elmer Model 1600 spectrometer or JASCO FT/IR-8900
® Fourier Transform Infrared Microsampling System. Mass
spectra were obtained on JEOL JMS-DX303 in the analytical
section of Osaka University. Elemental analyses were per-
formed in the analytical section of Osaka University. Thio-
cyanates were prepared according to the literature.11 Other
materials including phenylselenocyanate were obtained from
commercial supplies and purified by distillation or recrystal-
lization before use. The purification of the products was carried
out by MPLC (silica gel, 25-40 ¯m, length 310 mm, i.d.
25 mm), preparative TLC (PTLC) on Wakogel B-5F silica gel,
or using recycling preparative HPLC (Japan Analytical
Industry Co., Ltd., Model LC-908) equipped with JAIGEL-
1H and -2H columns (GPC) using CHCl3 as an eluent.
Procedure for the [Co2(CO)8]-Catalyzed Cyanothiolation
of 1-Octyne with PhSCN.
In a 50 mL stainless steel
autoclave with a magnetic stirring bar under an argon
atmosphere were placed [Co2(CO)8] (0.1 mmol), CH2Cl2
(1 mL), 1-octyne (1.0 mmol), and phenyl thiocyanate
(1.0 mmol). The vessel was purged three times with carbon
monoxide and then charged at 3 MPa. The reaction was
conducted with magnetic stirring for 11-84 h upon heating at
120-160 °C. After carbon monoxide was purged, the precip-
itates were filtered through Celite and concentrated in vacuo.
Purification of the product was carried out by MPLC eluted
with hexane:Et2O = 4:1, or using a recycling preparative
HPLC (Japan Analytical Industry Co., Ltd., Model LC-908)
equipped with JAIGEL-1H and -2H columns (GPC) using
CHCl3 as an eluent.
(Z)-3-(Phenylthio)-2-nonenenitrile ((Z)-3a) (Table 2):
Pale red-brown oil; 1H NMR (300 MHz, CDCl3): ¤ 0.83 (t,
J = 6.8 Hz, 3H), 1.14-1.25 (m, 6H), 1.39 (quint, J = 7.3 Hz,
2H), 2.15 (t, J = 7.6 Hz, 2H), 5.30 (s, 1H), 7.38-7.51 (m, 5H);
13C NMR (68 MHz, CDCl3): ¤ 13.9, 22.3, 28.2, 28.3, 31.3,
36.2, 93.7, 116.1, 129.4, 129.5, 129.6, 134.9, 165.1; IR (NaCl):
3060, 2958, 2929, 2857, 2212 (CN), 1574, 1441, 1069, 1024,
749, 705, 692 cm¹1; MS (EI): m/z = 245 (M+, 20). Anal.
(Z)-3-(Phenylthio)-2-heptenedinitrile
(3c)
(Table 5,
1
Entry 2): Brown oil; H NMR (300 MHz, CDCl3): ¤ 1.76
(quint, J = 7.0 Hz, 2H), 2.25 (t, J = 7.2 Hz, 2H), 2.36 (t,
J = 7.3 Hz, 2H), 5.41 (s, 1H), 7.35-7.52 (m, 5H); 13C NMR
(68 MHz, CDCl3): ¤ 16.1, 23.8, 34.5, 95.8, 115.4, 118.4, 128.4,
129.7, 130.0, 134.6, 162.3; IR (NaCl): 3048, 2943, 2246 (CN),
2212 (CN), 1573, 1475, 1455, 1441, 1424, 1024, 751, 705,
692 cm¹1; MS (EI): m/z = 229 ([M + H]+, 8.6). HRMS calcd
for C13H13N2S [M + H]+ 229.0799, found 229.0809.
4-Phenyl-3-(phenylthio)-2-butenenitrile [E/Z-Mixture]
(3d) (Table 5, Entry 3):
Pale yellow oil; 1H NMR (300
MHz, CDCl3): ¤ 3.42 (t, J = 0.75 Hz, 2H), 3.95 (s, 2H), 4.58 (s,
1H), 5.11 (t, J = 1.4 Hz, 1H), 6.93-7.49 (m, 20H); 13C NMR
(75 MHz, CDCl3): ¤ 42.2, 77.2, 77.2, 95.2, 95.3, 116.0, 127.4,
128.8, 128.9, 129.1, 129.5, 129.9, 135.4, 135.7, 164.3; IR